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May 25, 2022 9:59 AM EDT

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    NPORT-P
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          0001572661
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        S000054767
        C000172043
      
      
      
    
  
  
    
      Principal Exchange-Traded Funds
      811-23029
      0001572661
      549300AG76V5U32HWF10
      801 Grand Avenue
      DES MOINES
      
      50309
      515-235-1719
      Principal Spectrum Preferred Securities Active ETF
      S000054767
      549300ZZZ8ISR58H5107
      2022-06-30
      2022-03-31
      N
    
    
      396706850.70
      1302122.78
      395404727.92
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      0.00000000
      
        
          USD
          
          
        
      
      
      
      
        
        
        
      
      N
      
        
          
        
        
        
        
      
      
      
      
      
    
    
      
        COMERICA INC
        I9Q57JVPWHHZ3ZGBW498
        Comerica, Inc.
        200340AU1
        
          
        
        625000.00000000
        PA
        USD
        648437.50000000
        0.163993360274
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-07-01
          Fixed
          5.63000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        WELLS FARGO & COMPANY
        PBLD0EJDB5FWOLXP3B76
        Wells Fargo & Co.
        949746RN3
        
          
        
        5289000.00000000
        PA
        USD
        5525947.20000000
        1.397542014499
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-06-15
          Fixed
          5.88000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        TRANSCANADA TRUST
        549300Y0MFCAXLBWUV51
        Transcanada Trust
        89356BAE8
        
          
        
        8475000.00000000
        PA
        USD
        8458050.00000000
        2.139086713629
        Long
        DBT
        CORP
        CA
        N
        
        2
        
          2079-09-15
          Fixed
          5.50000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        AMERICAN EXPRESS CO
        R4PP93JZOLY261QX3811
        American Express Co.
        025816CH0
        
          
        
        11497000.00000000
        PA
        USD
        10477216.10000000
        2.649744770406
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-09-15
          Fixed
          3.55000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        DOMINION ENERGY INC
        ILUL7B6Z54MRYCF6H308
        Dominion Energy, Inc.
        25746UDD8
        
          
        
        13749000.00000000
        PA
        USD
        13611510.00000000
        3.442424695223
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2024-12-15
          Fixed
          4.65000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        BP CAPITAL MARKETS PLC
        549300CRVT18MXX0AG93
        BP Capital Markets PLC
        05565QDV7
        
          
        
        1898000.00000000
        PA
        USD
        1902745.00000000
        0.481214529226
        Long
        DBT
        CORP
        GB
        N
        
        2
        
          2030-03-22
          Fixed
          4.88000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        AMERICAN INTL GROUP
        ODVCVCQG2BP6VHV36M30
        American International Group, Inc.
        026874DM6
        
          
        
        1602000.00000000
        PA
        USD
        1611131.40000000
        0.407463868344
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2048-04-01
          Fixed
          5.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CITIGROUP INC
        6SHGI4ZSSLCXXQSBB395
        Citigroup, Inc.
        172967MV0
        
          
        
        6905000.00000000
        PA
        USD
        6507962.50000000
        1.645899009411
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-02-18
          Fixed
          3.88000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CMS ENERGY CORP
        549300IA9XFBAGNIBW29
        CMS Energy Corp.
        125896BV1
        
          
        
        3055000.00000000
        PA
        USD
        2696037.50000000
        0.681842504560
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2050-12-01
          Fixed
          3.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        GOLDMAN SACHS GROUP INC
        784F5XWPLTWKTBV3E584
        Goldman Sachs Group, Inc.
        38141GYU2
        
          
        
        5192000.00000000
        PA
        USD
        4868798.00000000
        1.231345418051
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-11-10
          Fixed
          4.13000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        BANK OF MONTREAL
        NQQ6HPCNCCU6TUTQYE16
        Bank of Montreal
        06368B5P9
        
          
        
        3546000.00000000
        PA
        USD
        3516568.20000000
        0.889359168388
        Long
        DBT
        CORP
        CA
        N
        
        2
        
          2024-08-25
          Fixed
          4.80000000
          N
          N
          N
        
        
          N
          N
          
        
      
      
        JPMorgan Chase & Co
        8I5DZWZKVSZI1NUHU748
        JPMorgan Chase & Co.
        46625HJQ4
        
          
        
        5002000.00000000
        PA
        USD
        5219887.12000000
        1.320137760481
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2024-02-01
          Fixed
          6.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        Citigroup Inc
        6SHGI4ZSSLCXXQSBB395
        Citigroup, Inc.
        172967JM4
        
          
        
        2439000.00000000
        PA
        USD
        2486072.70000000
        0.628741267985
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-05-15
          Fixed
          5.95000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        AMERICAN ELECTRIC POWER
        1B4S6S7G0TW5EE83BO58
        American Electric Power Co., Inc.
        025537AU5
        
          
        
        3484000.00000000
        PA
        USD
        3218664.41000000
        0.814017684343
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2062-02-15
          Fixed
          3.88000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CLOVERIE PLC ZURICH INS
        5493002N598MXOKUEF55
        Cloverie PLC for Zurich Insurance Co. Ltd.
        000000000
        
          
        
        5600000.00000000
        PA
        USD
        5866896.00000000
        1.483769815010
        Long
        DBT
        CORP
        IE
        
        N
        
        2
        
          2046-06-24
          Fixed
          5.63000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        ARGENTUM (ZURICH INS)
        50ZCTKCMUDIABGHX3R52
        Argentum Netherlands BV for Zurich Insurance Co. Ltd.
        000000000
        
          
        
        4000000.00000000
        PA
        USD
        4120080.00000000
        1.041990575498
        Long
        DBT
        CORP
        NL
        
        N
        
        2
        
          2048-06-01
          Fixed
          5.13000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        ALGONQUIN PWR & UTILITY
        549300K5VIUTJXQL7X75
        Algonquin Power & Utilities Corp.
        015857AH8
        
          
        
        3666000.00000000
        PA
        USD
        3418178.40000000
        0.864475854393
        Long
        DBT
        CORP
        CA
        N
        
        2
        
          2082-01-18
          Fixed
          4.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        METLIFE INC
        C4BXATY60WC6XEOZDX54
        MetLife, Inc.
        59156RCA4
        
          
        
        7178000.00000000
        PA
        USD
        7078943.60000000
        1.790303226073
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-09-15
          Fixed
          3.85000000
          N
          N
          N
        
        
          N
          N
          
        
      
      
        Voya Financial Inc
        549300T065Z4KJ686G75
        Voya Financial, Inc.
        929089AG5
        
          
        
        3861000.00000000
        PA
        USD
        3832042.50000000
        0.969144329699
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2023-09-15
          Fixed
          6.13000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        TRUIST FINANCIAL CORP
        549300DRQQI75D2JP341
        Truist Financial Corp.
        89832QAE9
        
          
        
        1726000.00000000
        PA
        USD
        1767424.00000000
        0.446991114470
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-09-01
          Fixed
          4.95000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        AXA SA
        F5WCUMTUM4RKZ1MAIE39
        AXA SA
        054536AC1
        
          
        
        5119000.00000000
        PA
        USD
        6534045.17000000
        1.652495458102
        Long
        DBT
        CORP
        FR
        N
        
        2
        
          2036-12-14
          Fixed
          6.38000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        WELLS FARGO & COMPANY
        PBLD0EJDB5FWOLXP3B76
        Wells Fargo & Co.
        949746TD3
        
          
        
        12125000.00000000
        PA
        USD
        11622418.75000000
        2.939372731109
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-03-15
          Fixed
          3.90000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        ALLY FINANCIAL INC
        549300JBN1OSM8YNAI90
        Ally Financial, Inc.
        02005NBN9
        
          
        
        587000.00000000
        PA
        USD
        534170.00000000
        0.135094489843
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2028-05-15
          Fixed
          4.70000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        ALLY FINANCIAL INC
        549300JBN1OSM8YNAI90
        Ally Financial, Inc.
        02005NBM1
        
          
        
        5087000.00000000
        PA
        USD
        4788443.97000000
        1.211023448098
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-05-15
          Fixed
          4.70000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        SOUTHERN CO
        549300FC3G3YU2FBZD92
        Southern Co.
        842587DF1
        
          
        
        2710000.00000000
        PA
        USD
        2621925.00000000
        0.663099051392
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2051-01-15
          Fixed
          4.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        HUNTINGTON BANCSHARES
        549300XTVCVV9I7B5T19
        Huntington Bancshares, Inc.
        446150AV6
        
          
        
        2141000.00000000
        PA
        USD
        2119590.00000000
        0.536055805693
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2027-10-15
          Fixed
          4.45000000
          N
          N
          N
        
        
          N
          N
          
        
      
      
        BANK OF NY MELLON CORP
        WFLLPEPC7FZXENRZV188
        Bank of New York Mellon Corp.
        064058AH3
        
          
        
        734000.00000000
        PA
        USD
        751616.00000000
        0.190087762469
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-09-20
          Fixed
          4.70000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        BP CAPITAL MARKETS PLC
        549300CRVT18MXX0AG93
        BP Capital Markets PLC
        05565QDU9
        
          
        
        5312000.00000000
        PA
        USD
        5341216.00000000
        1.350822492208
        Long
        DBT
        CORP
        GB
        N
        
        2
        
          2025-06-22
          Fixed
          4.38000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CITIZENS FINANCIAL GROUP
        2138004JDDA4ZQUPFW65
        Citizens Financial Group, Inc.
        174610BD6
        
          
        
        2343000.00000000
        PA
        USD
        2149702.50000000
        0.543671420245
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-10-06
          Fixed
          4.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        Prudential Financial Inc
        5PRBRS5FEH7NREC8OR45
        Prudential Financial, Inc.
        744320AM4
        
          
        
        6036000.00000000
        PA
        USD
        6073725.00000000
        1.536077990759
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2043-06-15
          Fixed
          5.63000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        ENTERPRISE PRODUCTS OPER
        5493004LGN656HWLDA30
        Enterprise Products Operating LLC
        29379VBN2
        
          
        
        3861000.00000000
        PA
        USD
        3629777.88000000
        0.917990510405
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2077-08-16
          Fixed
          5.25000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        JPMorgan Chase & Co
        8I5DZWZKVSZI1NUHU748
        JPMorgan Chase & Co.
        48126HAA8
        
          
        
        4252000.00000000
        PA
        USD
        4305150.00000000
        1.088795782146
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2023-08-01
          Fixed
          6.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        ZURICH FINANCE IRELAND
        549300E0FVHYR37EGX65
        Zurich Finance Ireland Designated Activity Co.
        000000000
        
          
        
        1000000.00000000
        PA
        USD
        882500.00000000
        0.223189035862
        Long
        DBT
        CORP
        IE
        
        N
        
        2
        
          2051-04-19
          Fixed
          3.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        BANK OF NY MELLON CORP
        WFLLPEPC7FZXENRZV188
        Bank of New York Mellon Corp.
        064058AL4
        
          
        
        2908000.00000000
        PA
        USD
        2688155.20000000
        0.679849028144
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-12-20
          Fixed
          3.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        BANK OF AMERICA CORP
        9DJT3UXIJIZJI4WXO774
        Bank of America Corp.
        060505GB4
        
          
        
        4714000.00000000
        PA
        USD
        4430217.20000000
        1.120425955274
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2027-01-27
          Fixed
          4.38000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        HUNTINGTON BANCSHARES
        549300XTVCVV9I7B5T19
        Huntington Bancshares, Inc.
        446150AT1
        
          
        
        6928000.00000000
        PA
        USD
        7215512.14000000
        1.824842150461
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2030-07-15
          Fixed
          5.63000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        SVB FINANCIAL GROUP
        549300D2KJ20JMXE7542
        SVB Financial Group
        78486QAP6
        
          
        
        4963000.00000000
        PA
        USD
        4590775.00000000
        1.161031893611
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-11-15
          Fixed
          4.25000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        FIFTH THIRD BANCORP
        THRNG6BD57P9QWTQLG42
        Fifth Third Bancorp
        316773DB3
        
          
        
        1014000.00000000
        PA
        USD
        996255.00000000
        0.251958292264
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-09-30
          Fixed
          4.50000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CMS ENERGY CORP
        549300IA9XFBAGNIBW29
        CMS Energy Corp.
        125896BU3
        
          
        
        2971000.00000000
        PA
        USD
        2941290.00000000
        0.743868191832
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2050-06-01
          Fixed
          4.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        SUMITOMO LIFE INSUR
        549300I5OQCDADQSPI57
        Sumitomo Life Insurance Co.
        86564CAA8
        
          
        
        7749000.00000000
        PA
        USD
        8076007.80000000
        2.042466169406
        Long
        DBT
        CORP
        JP
        N
        
        2
        
          2073-09-20
          Fixed
          6.50000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        TRUIST FINANCIAL CORP
        549300DRQQI75D2JP341
        Truist Financial Corp.
        89832QAD1
        
          
        
        7720000.00000000
        PA
        USD
        7584900.00000000
        1.918262343472
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2024-09-01
          Fixed
          4.80000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        ENBRIDGE INC
        98TPTUM4IVMFCZBCUR27
        Enbridge, Inc.
        29250NBC8
        
          
        
        2240000.00000000
        PA
        USD
        2318400.00000000
        0.586335932854
        Long
        DBT
        CORP
        CA
        N
        
        2
        
          2080-07-15
          Fixed
          5.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        EQUITABLE HOLDINGS INC
        549300FIBAKMNHPZ4009
        Equitable Holdings, Inc.
        29452EAA9
        
          
        
        3961000.00000000
        PA
        USD
        3891682.50000000
        0.984227609131
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-09-15
          Fixed
          4.95000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        US BANCORP
        N1GZ7BBF3NP8GI976H15
        U.S. Bancorp
        902973BC9
        
          
        
        10250000.00000000
        PA
        USD
        9276250.00000000
        2.346013930788
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2027-01-15
          Fixed
          3.70000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        DUKE ENERGY CORP
        I1BZKREC126H0VB1BL91
        Duke Energy Corp.
        26441CBP9
        
          
        
        3132000.00000000
        PA
        USD
        2776088.63000000
        0.702087869460
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2082-01-15
          Fixed
          3.25000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CHARLES SCHWAB CORP
        549300VSGCJ7E698NM85
        Charles Schwab Corp.
        808513BD6
        
          
        
        4626000.00000000
        PA
        USD
        4764780.00000000
        1.205038701753
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-06-01
          Fixed
          5.38000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        JPMORGAN CHASE & CO
        8I5DZWZKVSZI1NUHU748
        JPMorgan Chase & Co.
        48128BAN1
        
          
        
        7886000.00000000
        PA
        USD
        7373410.00000000
        1.864775375546
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-06-01
          Fixed
          3.65000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CHARLES SCHWAB CORP
        549300VSGCJ7E698NM85
        Charles Schwab Corp.
        808513BK0
        
          
        
        10399000.00000000
        PA
        USD
        9957042.50000000
        2.518190046026
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-06-01
          Fixed
          4.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        HSBC CAPITAL FUNDING USD
        213800HMY2DB765NHE46
        HSBC Capital Funding Dollar 1 LP
        000000000
        
          
        
        5586000.00000000
        PA
        USD
        8546580.00000000
        2.161476430734
        Long
        DBT
        CORP
        JE
        
        N
        
        2
        
          2030-06-30
          Fixed
          10.18000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        M&T BANK CORPORATION
        549300WYXDDBYRASEG81
        M&T Bank Corp.
        55261FAN4
        
          
        
        3938000.00000000
        PA
        USD
        3539198.74000000
        0.895082554682
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-09-01
          Fixed
          3.50000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        SCENTRE GROUP TRUST 2
        549300VRF0U0JH8TBJ74
        Scentre Group Trust 2
        76025LAA2
        
          
        
        1079000.00000000
        PA
        USD
        1058768.75000000
        0.267768358656
        Long
        DBT
        
        AU
        N
        
        2
        
          2080-09-24
          Fixed
          4.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        MetLife Inc
        C4BXATY60WC6XEOZDX54
        MetLife, Inc.
        59156RBS6
        
          
        
        5629000.00000000
        PA
        USD
        7309812.14000000
        1.848691131856
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2038-04-08
          Fixed
          9.25000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        Bank of America Corp
        9DJT3UXIJIZJI4WXO774
        Bank of America Corp.
        060505EU4
        
          
        
        766000.00000000
        PA
        USD
        814602.70000000
        0.206017440480
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-03-10
          Fixed
          6.30000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CITIZENS FINANCIAL GROUP
        2138004JDDA4ZQUPFW65
        Citizens Financial Group, Inc.
        174610AQ8
        
          
        
        2826000.00000000
        PA
        USD
        2762415.00000000
        0.698629734280
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2024-04-06
          Fixed
          6.38000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        NiSource Inc
        549300D8GOWWH0SJB189
        NiSource, Inc.
        65473PAG0
        
          
        
        6070000.00000000
        PA
        USD
        5948600.00000000
        1.504433199696
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2023-06-15
          Fixed
          5.65000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        GOLDMAN SACHS GROUP INC
        784F5XWPLTWKTBV3E584
        Goldman Sachs Group, Inc.
        38144GAG6
        
          
        
        1965000.00000000
        PA
        USD
        1797975.00000000
        0.454717628051
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-08-10
          Fixed
          3.65000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        ALLSTATE CORP
        OBT0W1ED8G0NWVOLOJ77
        Allstate Corp.
        020002BB6
        
          
        
        3861000.00000000
        PA
        USD
        3841695.00000000
        0.971585499295
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2053-08-15
          Fixed
          5.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        GOLDMAN SACHS GROUP INC
        784F5XWPLTWKTBV3E584
        Goldman Sachs Group, Inc.
        38148BAE8
        
          
        
        5772000.00000000
        PA
        USD
        5889171.77000000
        1.489403478046
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2024-08-10
          Fixed
          5.50000000
          N
          N
          N
        
        
          N
          N
          
        
      
      
        ARGENTUM (SWISS RE LTD)
        724500RPEZI5VVQQWE89
        Argentum Netherlands BV for Swiss Re Ltd.
        000000000
        
          
        
        5600000.00000000
        PA
        USD
        5779984.00000000
        1.461789298879
        Long
        DBT
        CORP
        NL
        
        N
        
        2
        
          2052-08-15
          Fixed
          5.63000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        STANLEY BLACK & DECKER I
        549300DJ09SMTO561131
        Stanley Black & Decker, Inc.
        854502AM3
        
          
        
        3861000.00000000
        PA
        USD
        3821347.53000000
        0.966439513786
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2060-03-15
          Fixed
          4.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        PRUDENTIAL FINANCIAL INC
        5PRBRS5FEH7NREC8OR45
        Prudential Financial, Inc.
        744320BH4
        
          
        
        10121000.00000000
        PA
        USD
        9274884.50000000
        2.345668588433
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2050-10-01
          Fixed
          3.70000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        MEIJI YASUDA LIFE INSURA
        549300SLU4LP6YMRLK07
        Meiji Yasuda Life Insurance Co.
        585270AA9
        
          
        
        3861000.00000000
        PA
        USD
        4020768.18000000
        1.016874077644
        Long
        DBT
        CORP
        JP
        N
        
        2
        
          2045-10-20
          Fixed
          5.20000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        Principal Government Money Market Fund
        549300WWK3YB7DNN4U34
        Principal Government Money Market Fund
        000000000
        
          
        
        1116810.00000000
        NS
        USD
        1116810.00000000
        0.282447305543
        Long
        STIV
        RF
        US
        N
        
        1
        
          
          N
          N
        
      
      
        BANK OF NY MELLON CORP
        WFLLPEPC7FZXENRZV188
        Bank of New York Mellon Corp.
        064058AJ9
        
          
        
        15141000.00000000
        PA
        USD
        14383950.00000000
        3.637778960222
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-03-20
          Fixed
          3.70000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        SVB FINANCIAL GROUP
        549300D2KJ20JMXE7542
        SVB Financial Group
        78486QAJ0
        
          
        
        2586000.00000000
        PA
        USD
        2392050.00000000
        0.604962417263
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-05-15
          Fixed
          4.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        Emera Inc
        NQZVQT2P5IUF2PGA1Q48
        Emera, Inc.
        290876AD3
        
          
        
        6939000.00000000
        PA
        USD
        7303297.50000000
        1.847043544071
        Long
        DBT
        CORP
        CA
        N
        
        2
        
          2076-06-15
          Fixed
          6.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CITIGROUP INC
        6SHGI4ZSSLCXXQSBB395
        Citigroup, Inc.
        172967MU2
        
          
        
        9288000.00000000
        PA
        USD
        8916480.00000000
        2.255026146729
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-12-10
          Fixed
          4.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        DUKE ENERGY CORP
        I1BZKREC126H0VB1BL91
        Duke Energy Corp.
        26441CBG9
        
          
        
        9356000.00000000
        PA
        USD
        9455454.37000000
        2.391335687800
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2024-09-16
          Fixed
          4.88000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        Vodafone Group PLC
        213800TB53ELEUKM7Q61
        Vodafone Group PLC
        92857WBQ2
        
          
        
        4533000.00000000
        PA
        USD
        5005429.26000000
        1.265900204666
        Long
        DBT
        CORP
        GB
        N
        
        2
        
          2079-04-04
          Fixed
          7.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        SUMITOMO LIFE INSUR
        549300I5OQCDADQSPI57
        Sumitomo Life Insurance Co.
        86564CAC4
        
          
        
        4672000.00000000
        PA
        USD
        4490726.40000000
        1.135729060100
        Long
        DBT
        CORP
        JP
        N
        
        2
        
          2081-04-15
          Fixed
          3.38000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CAPITAL ONE FINANCIAL CO
        ZUE8T73ROZOF6FLBAR73
        Capital One Financial Corp.
        14040HCF0
        
          
        
        4845000.00000000
        PA
        USD
        4506334.50000000
        1.139676433234
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-09-01
          Fixed
          3.95000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        PNC FINANCIAL SERVICES
        CFGNEKW0P8842LEUIA51
        PNC Financial Services Group, Inc.
        693475BC8
        
          
        
        2564000.00000000
        PA
        USD
        2308882.00000000
        0.583928779037
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-09-15
          Fixed
          3.40000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        GOLDMAN SACHS GROUP INC
        784F5XWPLTWKTBV3E584
        Goldman Sachs Group, Inc.
        38144GAE1
        
          
        
        1540000.00000000
        PA
        USD
        1427387.50000000
        0.360994039577
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2026-05-10
          Fixed
          3.80000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        CITIZENS FINANCIAL GROUP
        2138004JDDA4ZQUPFW65
        Citizens Financial Group, Inc.
        174610AU9
        
          
        
        3081000.00000000
        PA
        USD
        3204394.05000000
        0.810408632910
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-10-06
          Fixed
          5.65000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        Enbridge Inc
        98TPTUM4IVMFCZBCUR27
        Enbridge, Inc.
        29250NAN5
        
          
        
        5772000.00000000
        PA
        USD
        5916376.54000000
        1.496283711912
        Long
        DBT
        CORP
        CA
        N
        
        2
        
          2077-01-15
          Fixed
          6.00000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        NIPPON LIFE INSURANCE
        549300Y0HHMFW3EVWY08
        Nippon Life Insurance Co.
        654579AH4
        
          
        
        5067000.00000000
        PA
        USD
        4547632.50000000
        1.150120921396
        Long
        DBT
        CORP
        JP
        N
        
        2
        
          2051-01-21
          Fixed
          2.75000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        DISCOVER FINANCIAL SVS
        Z1YLO2USPORE63VVUL20
        Discover Financial Services
        254709AQ1
        
          
        
        6323000.00000000
        PA
        USD
        6580219.64000000
        1.664173231972
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2025-06-23
          Fixed
          6.13000000
          N
          N
          N
        
        
          N
          N
          
        
      
      
        SCENTRE GROUP TRUST 2
        549300VRF0U0JH8TBJ74
        Scentre Group Trust 2
        76025LAB0
        
          
        
        2426000.00000000
        PA
        USD
        2380512.50000000
        0.602044520945
        Long
        DBT
        
        AU
        N
        
        2
        
          2080-09-24
          Fixed
          5.13000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        NIPPON LIFE INSURANCE
        549300Y0HHMFW3EVWY08
        Nippon Life Insurance Co.
        654579AK7
        
          
        
        2888000.00000000
        PA
        USD
        2614410.72000000
        0.661198649230
        Long
        DBT
        CORP
        JP
        N
        
        2
        
          2051-09-16
          Fixed
          2.90000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        LIBERTY MUTUAL GROUP INC
        QUR0DG15Z6FFGYCHH861
        Liberty Mutual Group, Inc.
        53079EBM5
        
          
        
        3107000.00000000
        PA
        USD
        2928347.50000000
        0.740594963394
        Long
        DBT
        CORP
        US
        N
        
        2
        
          2051-12-15
          Fixed
          4.13000000
          N
          N
          N
        
        
          N
          N
          N
        
      
      
        State Street Global Advisors
        549300BZ5TGIFZUZDZ37
        State Street Institutional U.S. Government Money Market Fund
        857492706
        
          
        
        4937085.08000000
        NS
        USD
        4937085.08000000
        1.248615590908
        Long
        STIV
        RF
        US
        N
        
        1
        
          N
          N
          N
        
      
      
        BANK OF NOVA SCOTIA
        L3I9ZG2KFGXZ61BMYR72
        Bank of Nova Scotia
        064159VJ2
        
          
        
        4915000.00000000
        PA
        USD
        4915000.00000000
        1.243030154407
        Long
        DBT
        CORP
        CA
        N
        
        2
        
          2025-06-04
          Fixed
          4.90000000
          N
          N
          N
        
        
          N
          N
          N
        
      
    
    
      
      
    
    
      2022-04-27
      Principal Exchange-Traded Funds
      Megan Hoffmann
      Megan Hoffmann
      Vice President and Controller
    
  
  XXXX


	Schedule of Investments
	Principal Active High Yield ETF
	March 31, 2022 (unaudited)

COMMON STOCKS — 0.29%		Shares Held		Value

REITs — 0.29%
CBL & Associates Properties, Inc. ^(a)		20,039	$	659,083
TOTAL COMMON STOCKS			$	659,083
		Principal
BONDS — 86.77%		Amount		Value

Aerospace & Defense — 1.80%
Bombardier, Inc.
7.13%, 06/15/2026 ^(b)	$	808,000	$	791,840
Triumph Group, Inc.
7.75%, 08/15/2025		3,158,000		3,181,306
8.88%, 06/01/2024 ^(b)		174,000		183,779
			$	4,156,925

Airlines — 0.10%
United Airlines Pass-Through Trust
3.65%, 07/07/2027		249,157		235,099

Auto Manufacturers — 1.75%
Ford Motor Co.
3.25%, 02/12/2032		1,431,000		1,278,069
Ford Motor Credit Co. LLC
3.38%, 11/13/2025		1,801,000		1,760,378
4.39%, 01/08/2026		206,000		205,467
4.54%, 08/01/2026		797,000		795,824
			$	4,039,738

Auto Parts & Equipment — 1.50%
Tenneco, Inc.
7.88%, 01/15/2029 ^(b)		3,291,000		3,467,891

Banks — 1.42%
Deutsche Bank AG
(5-year Treasury Constant Maturity Rate + 4.52%),
6.00%, 10/30/2025 ^(c),(d),(e)		3,360,000		3,276,000

Chemicals — 3.60%
Consolidated Energy Finance SA
5.63%, 10/15/2028 ^(b)		3,395,000		3,140,375
Kobe U.S. Midco 2, Inc.
9.25%, PIK 10.00%; 11/01/2026 ^(b),(f)		899,000		872,030
Olympus Water U.S. Holding Corp.
6.25%, 10/01/2029 ^(b),(g)		2,360,000		2,088,600
Tronox, Inc.
4.63%, 03/15/2029 ^(b)		2,360,000		2,209,550
			$	8,310,555

Commercial Services — 5.00%
Ahern Rentals, Inc.
7.38%, 05/15/2023 ^(b)		2,130,000		1,975,575
Albion Financing 1 SARL/Aggreko Holdings, Inc.
6.13%, 10/15/2026 ^(b)		1,953,000		1,884,645
Garda World Security Corp.
6.00%, 06/01/2029 ^(b)		348,000		312,596
9.50%, 11/01/2027 ^(b)		2,205,000		2,260,125
WASH Multifamily Acquisition, Inc.
5.75%, 04/15/2026 ^(b)		2,936,000		2,943,340

See accompanying notes.


Schedule of Investments
Principal Active High Yield ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Commercial Services (continued)
ZipRecruiter, Inc.
5.00%, 01/15/2030 ^(b)	$	2,229,000	$	2,176,775
			$	11,553,056

Construction Materials — 1.51%
SRM Escrow Issuer LLC
6.00%, 11/01/2028 ^(b)		3,546,000		3,497,278

Diversified Financial Services — 5.59%
AerCap Holdings NV
(5-year Treasury Constant Maturity Rate + 4.54%),
5.88%, 10/10/2079 ^(c)		3,324,000		3,191,040
Coinbase Global, Inc.
3.63%, 10/01/2031 ^(b)		569,000		485,073
Credit Acceptance Corp.
6.63%, 03/15/2026		3,238,000		3,302,760
Global Aircraft Leasing Co. Ltd.
6.50%, PIK 7.25%; 09/15/2024 ^(b),(f)		3,322,529		3,018,634
OneMain Finance Corp.
4.00%, 09/15/2030		2,315,000		2,042,987
6.63%, 01/15/2028		828,000		867,330
			$	12,907,824

Electric — 2.51%
Clearway Energy Operating LLC
4.75%, 03/15/2028 ^(b)		2,270,000		2,279,829
GenOn Energy, Inc.
0.00%, 10/15/2049 ^(a),(h),(i)		3,100,000		—
Vistra Corp.
(5-year Treasury Constant Maturity Rate + 5.74%),
7.00%, 12/15/2026 ^(b),(c),(d)		1,487,000		1,447,966
Vistra Operations Co. LLC
4.38%, 05/01/2029 ^(b)		2,179,000		2,059,155
			$	5,786,950

Engineering & Construction — 0.99%
MasTec, Inc.
4.50%, 08/15/2028 ^(b)		2,296,000		2,274,815

Entertainment — 8.16%
Boyne USA, Inc.
4.75%, 05/15/2029 ^(b)		3,128,000		3,002,880
Caesars Entertainment, Inc.
6.25%, 07/01/2025 ^(b)		384,000		396,457
8.13%, 07/01/2027 ^(b)		1,781,000		1,908,261
CCM Merger, Inc.
6.38%, 05/01/2026 ^(b)		3,309,000		3,342,090
Cinemark USA, Inc.
5.25%, 07/15/2028 ^(b)		1,301,000		1,214,978
International Game Technology PLC
5.25%, 01/15/2029 ^(b)		2,581,000		2,574,548
Lions Gate Capital Holdings LLC
5.50%, 04/15/2029 ^(b)		3,205,000		3,088,819
Peninsula Pacific Entertainment LLC/Peninsula Pacific Entertainment Finance,
Inc.
8.50%, 11/15/2027 ^(b)		2,993,000		3,311,006
			$	18,839,039

See accompanying notes.


	Schedule of Investments
	Principal Active High Yield ETF
	March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Food — 4.91%
Chobani LLC/Chobani Finance Corp., Inc.
7.50%, 04/15/2025 ^(b)	$	2,729,000	$	2,638,397
Fresh Market, Inc.
9.75%, 05/01/2023 ^(b)		3,440,000		3,374,038
Kraft Heinz Foods Co.
3.75%, 04/01/2030		2,283,000		2,273,206
Pilgrim's Pride Corp.
3.50%, 03/01/2032 ^(b)		2,863,000		2,499,356
4.25%, 04/15/2031 ^(b)		591,000		546,675
			$	11,331,672

Forest Products & Paper — 0.86%
Mercer International, Inc.
5.13%, 02/01/2029		2,059,000		1,986,935

Healthcare — Services — 5.18%
Acadia Healthcare Co., Inc.
5.00%, 04/15/2029 ^(b)		3,071,000		3,031,806
Centene Corp.
2.50%, 03/01/2031		509,000		449,208
3.38%, 02/15/2030		1,841,000		1,732,261
CHS/Community Health Systems, Inc.
6.00%, 01/15/2029 ^(b)		3,284,000		3,318,302
LifePoint Health, Inc.
5.38%, 01/15/2029 ^(b)		3,616,000		3,416,695
			$	11,948,272

Home Builders — 1.17%
Empire Communities Corp.
7.00%, 12/15/2025 ^(b)		120,000		118,560
Forestar Group, Inc.
3.85%, 05/15/2026 ^(b)		544,000		507,280
5.00%, 03/01/2028 ^(b)		2,225,000		2,085,938
			$	2,711,778

Insurance — 0.80%
Acrisure LLC/Acrisure Finance, Inc.
4.25%, 02/15/2029 ^(b)		409,000		371,544
7.00%, 11/15/2025 ^(b)		1,480,000		1,479,556
			$	1,851,100

Investment Companies — 0.91%
Compass Group Diversified Holdings LLC
5.25%, 04/15/2029 ^(b)		2,242,000		2,107,480

Iron & Steel — 0.93%
TMS International Corp.
6.25%, 04/15/2029 ^(b)		2,270,000		2,156,500

Leisure Time — 0.99%
Life Time, Inc.
5.75%, 01/15/2026 ^(b)		2,285,000		2,282,692

Media — 4.87%
DIRECTV Holdings LLC/DIRECTV Financing Co., Inc.
5.88%, 08/15/2027 ^(b)		3,385,000		3,329,994
DISH DBS Corp.
5.13%, 06/01/2029		447,000		380,661

See accompanying notes.


Schedule of Investments
Principal Active High Yield ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Media (continued)
DISH DBS Corp. (continued)
5.25%, 12/01/2026 ^(b)	$	3,284	$	3,128
5.88%, 11/15/2024		1,185,000		1,182,037
7.38%, 07/01/2028		1,973,000		1,869,417
Scripps Escrow II, Inc.
5.38%, 01/15/2031 ^(b)		939,000		899,093
Sirius XM Radio, Inc.
3.13%, 09/01/2026 ^(b)		2,199,000		2,079,095
UPC Holding BV
5.50%, 01/15/2028 ^(b)		1,529,000		1,510,239
			$	11,253,664

Mining — 4.61%
Copper Mountain Mining Corp.
8.00%, 04/09/2026 ^(b)		2,130,600		2,162,559
First Quantum Minerals Ltd.
6.88%, 10/15/2027 ^(b)		2,947,000		3,086,983
Novelis Corp.
3.88%, 08/15/2031 ^(b)		2,911,000		2,662,575
Taseko Mines Ltd.
7.00%, 02/15/2026 ^(b)		2,641,000		2,719,570
			$	10,631,687

Oil & Gas — 6.28%
Aethon United BR LP/Aethon United Finance Corp.
8.25%, 02/15/2026 ^(b)		3,138,000		3,256,303
Antero Resources Corp.
7.63%, 02/01/2029 ^(b)		2,058,000		2,224,554
Ascent Resources Utica Holdings LLC/ARU Finance Corp.
7.00%, 11/01/2026 ^(b)		877,000		899,355
Comstock Resources, Inc.
5.88%, 01/15/2030 ^(b)		1,276,000		1,257,243
MEG Energy Corp.
7.13%, 02/01/2027 ^(b)		2,154,000		2,255,238
Occidental Petroleum Corp.
3.40%, 04/15/2026		874,000		868,537
4.10%, 02/15/2047		2,004,000		1,853,700
4.40%, 04/15/2046		207,000		196,650
6.13%, 01/01/2031		307,000		345,375
6.63%, 09/01/2030		1,165,000		1,336,837
			$	14,493,792

Oil & Gas Services — 0.46%
Archrock Partners LP/Archrock Partners Finance Corp.
6.25%, 04/01/2028 ^(b)		1,080,000		1,064,437

Packaging & Containers — 1.31%
Clydesdale Acquisition Holdings, Inc.
6.63%, 04/15/2029		330,000		333,713
8.75%, 04/15/2030		1,410,000		1,327,162
LABL, Inc.
5.88%, 11/01/2028 ^(b)		246,000		230,625
8.25%, 11/01/2029 ^(b)		1,286,000		1,134,895
			$	3,026,395

See accompanying notes.


Schedule of Investments
Principal Active High Yield ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Pharmaceuticals — 1.68%
BellRing Brands, Inc.
7.00%, 03/15/2030	$	1,999,000	$	2,041,479
Jazz Securities DAC
4.38%, 01/15/2029 ^(b)		1,886,000		1,827,062
			$	3,868,541

Pipelines — 6.62%
Antero Midstream Partners LP/Antero Midstream Finance Corp.
5.38%, 06/15/2029 ^(b)		2,166,000		2,163,791
5.75%, 03/01/2027 ^(b)		1,367,000		1,392,139
CNX Midstream Partners LP
4.75%, 04/15/2030 ^(b)		2,955,000		2,767,269
Crestwood Midstream Partners LP/Crestwood Midstream Finance Corp.
5.63%, 05/01/2027 ^(b)		3,385,000		3,353,993
Hess Midstream Operations LP
4.25%, 02/15/2030 ^(b)		2,476,000		2,336,354
Targa Resources Partners LP/Targa Resources Partners Finance Corp.
4.88%, 02/01/2031		3,248,000		3,280,480
			$	15,294,026

REITs — 2.18%
CBL & Associates HoldCo II LLC
10.00%, 11/15/2029		1,706,199		1,706,199
CBL & Associates LP
0.00%, 12/15/2026 ^(a),(h),(i)		6,000,000		—
Ladder Capital Finance Holdings LLLP/Ladder Capital Finance Corp.
4.75%, 06/15/2029 ^(b)		3,533,000		3,332,061
			$	5,038,260

Retail — 6.24%
At Home Group, Inc.
4.88%, 07/15/2028 ^(b)		1,868,000		1,662,520
Bath & Body Works, Inc.
5.25%, 02/01/2028		364,000		366,144
6.63%, 10/01/2030 ^(b)		1,039,000		1,090,950
9.38%, 07/01/2025 ^(b)		394,000		449,711
BCPE Ulysses Intermediate, Inc.
7.75%, PIK 8.50%; 04/01/2027 ^(b),(f)		2,714,000		2,462,955
Dave & Buster's, Inc.
7.63%, 11/01/2025 ^(b)		1,678,000		1,765,508
Fertitta Entertainment LLC/Fertitta Entertainment Finance Co., Inc.
4.63%, 01/15/2029 ^(b)		1,538,000		1,457,255
6.75%, 01/15/2030 ^(b)		1,044,000		960,449
LSF9 Atlantis Holdings LLC/Victra Finance Corp.
7.75%, 02/15/2026 ^(b)		2,250,000		2,161,496
Park River Holdings, Inc.
5.63%, 02/01/2029 ^(b)		1,659,000		1,340,024
Patrick Industries, Inc.
4.75%, 05/01/2029 ^(b)		798,000		686,280
			$	14,403,292

Telecommunications — 1.46%
DKT Finance ApS
9.38%, 06/17/2023 ^(b)		3,383,000		3,366,085

See accompanying notes.


Schedule of Investments
Principal Active High Yield ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Transportation — 1.38%
Navios Maritime Holdings, Inc./Navios Maritime Finance II US, Inc.
11.25%, 08/15/2022 ^(b)	$	1,057,000	$	1,046,430
Watco Cos., LLC/Watco Finance Corp.
6.50%, 06/15/2027 ^(b)		2,171,000		2,134,462
			$	3,180,892
TOTAL BONDS			$	200,342,670
		Principal
SENIOR FLOATING RATE INTERESTS — 10.38%		Amount		Value

Airlines — 2.44%
AAdvantage Loyalty IP Ltd., 2021 Term Loan
(3-month USD LIBOR + 4.75%),
5.50%, 04/20/2028	$	3,355,000	$	3,393,784
United Airlines, Inc., 2021 Term Loan B
(3-month USD LIBOR + 3.75%),
4.50%, 04/21/2028		2,272,782		2,242,485
			$	5,636,269

Entertainment — 0.37%
The Enterprise Development Authority, Term Loan B
(1-month USD LIBOR + 4.25%),
5.00%, 02/01/2028		865,823		857,164

Forest Products & Paper — 1.46%
Pixelle Specialty Solutions LLC, Term Loan B
(1-month USD LIBOR + 6.50%),
7.50%, 10/31/2024		3,445,000		3,369,658

Insurance — 2.19%
Acrisure LLC, 2020 Term Loan B
(1-month USD LIBOR + 3.50%),
3.96%, 02/15/2027		1,653,630		1,627,453
Asurion LLC, 2021 2nd Lien Term Loan B3
(1-month USD LIBOR + 5.25%),
5.71%, 02/03/2028		3,505,000		3,431,395
			$	5,058,848

Lodging — 0.52%
Fertitta Entertainment LLC, 2022 Term Loan B
(1-month Term Secured Overnight Financing Rate + 4.00%),
4.50%, 01/27/2029		1,211,224		1,203,654

Packaging & Containers — 1.14%
Valcour Packaging LLC, 2021 1st Lien Term Loan
(3-month USD LIBOR + 3.75%),
4.25%, 09/30/2028		1,600,000		1,560,000
Valcour Packaging LLC, 2021 2nd Lien Term Loan
(3-month USD LIBOR + 7.00%),
7.50%, 09/30/2029		1,125,000		1,068,750
			$	2,628,750

Pharmaceuticals — 2.16%
Bausch Health Cos., Inc., 2022 Term Loan B
0.00%, 01/27/2027 ^(j)		3,525,000		3,485,344

See accompanying notes.


	Schedule of Investments
	Principal Active High Yield ETF
	March 31, 2022 (unaudited)

			Principal
SENIOR FLOATING RATE INTERESTS (continued)			Amount		Value

Pharmaceuticals (continued)
Jazz Financing Lux SARL, USD Term Loan
	(1-month USD LIBOR + 3.50%),
	4.00%, 05/05/2028	$	1,515,043	$	1,508,043
				$	4,993,387

Retail — 0.10%
At Home Group, Inc., Term Loan B
	(3-month USD LIBOR + 4.25%),
	4.75%, 07/23/2028		233,825		223,450
TOTAL SENIOR FLOATING RATE INTERESTS				$	23,971,180
INVESTMENT COMPANIES — 2.80%			Shares Held		Value

Money Market Funds — 2.80%
Principal Government Money Market Fund — Institutional Class 0.00%, ^{(a),(k),(l),(m)}			108,750	$	108,750
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(m)			6,346,773		6,346,773
TOTAL INVESTMENT COMPANIES				$	6,455,523
Total Investments				$	231,428,456
Other Assets and Liabilities — (0.24)%					(542,911	)

Total Net Assets — 100.00%				$	230,885,545

^(a)	Non-income producing security.
^(b)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in
	transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these
	securities totaled $156,676,409 or 67.86% of net assets.
^(c)	Rate shown is as of period end. The rate may be a variable or floating rate or a fixed rate which may convert to a variable or
	floating rate in the future.
^(d)	Perpetual security. Perpetual securities pay an indefinite stream of interest, but they may be called by the issuer at an earlier
	date. Date shown, if any, reflects the next call date or final legal maturity date. Rate shown is as of period end.
^(e)	Security is a contingent convertible security, ("CoCo"). CoCo's are hybrid debt securities that may convert to equity or have
	their principal written down upon occurrence of certain "triggers". At the end of the period, the value of these securities
	totaled $3,276,000 or 1.42% of net assets.
^(f)	Payment in kind; the issuer has the option of paying additional securities in lieu of cash.
^(g)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $106,265 or
	0.05% of net assets.
^(h)	The value of these investments was determined using significant unobservable inputs, in good faith by the Advisor, under
	procedures established and periodically reviewed by the Board of Trustees.
⁽ⁱ⁾	Security is defaulted.
^(j)	This Senior Floating Rate Interest will settle after March 31, 2022, at which time the interest rate will be determined.
^(k)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate
	as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(l)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of
	these securities totaled $108,750 or 0.05% of net assets.
^(m)	Current yield shown is as of period end.

See accompanying notes.


			Schedule of Investments
			Principal Active High Yield ETF
			March 31, 2022 (unaudited)

Portfolio Summary (unaudited)
Sector					Percent
Consumer, Cyclical					23.35	%
Consumer, Non-cyclical					18.92	%
Financial					13.38	%
Energy					13.36	%
Basic Materials					11.46	%
Industrial					8.13	%
Communications					6.33	%
Money Market Funds					2.80	%
Utilities					2.51	%
Other Assets and Liabilities					(0.24	)%
TOTAL NET ASSETS					100.00	%

			June 30, 2021		Purchases		Sales		March 31, 2022
Affiliated Securities			Value		Cost		Proceeds		Value
Principal Government Money
Market Fund - Institutional Class
0.00	%	$	3,145,675	$	42,064,102	$	45,101,027	$	108,750
		$	3,145,675	$	42,064,102	$	45,101,027	$	108,750

							Realized Gain
					Realized		from		Change in
					Gain/(Loss) on		Capital Gain		Unrealized
			Income ^(a)		Investments		Distributions		Gain/(Loss)
Principal Government Money
Market Fund - Institutional Class
0.00	%	$	—	$	— $		—	$	—
		$	—	$	— $		—	$	—

^(a)Amount excludes earnings from securities lending collateral.

See accompanying notes.


Schedule of Investments
Principal Healthcare Innovators ETF
March 31, 2022 (unaudited)

COMMON STOCKS — 99.82%	Shares Held		Value

Biotechnology — 42.69%
2seventy bio, Inc. ^(a)	2,547	$	43,452
9 Meters Biopharma, Inc. ^(a)	28,865		17,299
ACADIA Pharmaceuticals, Inc. ^(a)	18,616		450,880
ADMA Biologics, Inc. ^(a)	15,041		27,525
Adverum Biotechnologies, Inc. ^(a)	11,117		14,563
Agenus, Inc. ^(a)	26,413		64,976
Akero Therapeutics, Inc. ^(a)	3,948		56,022
Alaunos Therapeutics, Inc. ^(a)	24,426		15,936
Albireo Pharma, Inc. ^(a)	2,185		65,179
Aldeyra Therapeutics, Inc. ^(a)	6,555		29,137
Allakos, Inc. ^(a)	6,239		35,562
Allogene Therapeutics, Inc. ^(a)	16,109		146,753
Alnylam Pharmaceuticals, Inc. ^(a)	13,681		2,233,970
Altimmune, Inc. ^(a)	4,501		27,411
ALX Oncology Holdings, Inc. ^(a)	4,573		77,284
Alzamend Neuro, Inc. ^(a)	9,846		12,111
Amicus Therapeutics, Inc. ^(a)	30,333		287,253
AnaptysBio, Inc. ^(a)	3,111		76,966
Anavex Life Sciences Corp. ^(a)	8,574		105,546
Annovis Bio, Inc. ^(a)	913		12,189
Apellis Pharmaceuticals, Inc. ^(a)	10,088		512,571
Applied Molecular Transport, Inc. ^(a)	4,355		32,750
Arcturus Therapeutics Holdings, Inc. ^(a)	2,980		80,341
Arcus Biosciences, Inc. ^(a)	8,312		262,327
Arcutis Biotherapeutics, Inc. ^(a)	5,690		109,589
Ardelyx, Inc. ^(a)	11,680		12,498
Arrowhead Pharmaceuticals, Inc. ^(a)	12,048		554,087
Atara Biotherapeutics, Inc. ^(a)	9,606		89,240
Atea Pharmaceuticals, Inc. ^(a)	9,379		67,716
Atossa Therapeutics, Inc. ^(a)	14,348		17,935
Atreca, Inc., Class A ^(a)	3,417		10,832
Avid Bioservices, Inc. ^(a)	6,949		141,551
Avidity Biosciences, Inc. ^(a)	5,176		95,601
Axsome Therapeutics, Inc. ^(a)	4,269		176,694
Beam Therapeutics, Inc. ^(a)	7,680		440,064
Berkeley Lights, Inc. ^(a)	7,605		54,072
BioAtla, Inc. ^(a)	3,656		18,280
BioCryst Pharmaceuticals, Inc. ^(a)	20,801		338,224
Biohaven Pharmaceutical Holding Co. Ltd. ^(a)	7,541		894,136
BioMarin Pharmaceutical, Inc. ^(a)	21,107		1,627,350
Bluebird Bio, Inc. ^(a)	7,654		37,122
Blueprint Medicines Corp. ^(a)	6,777		432,915
Bridgebio Pharma, Inc. ^(a)	17,269		175,280
Brooklyn ImmunoTherapeutics, Inc. ^(a),(b)	5,864		12,021
C4 Therapeutics, Inc. ^(a)	5,489		133,163
Cara Therapeutics, Inc. ^(a)	5,678		68,988
Cardiff Oncology, Inc. ^(a)	4,478		11,105
Cassava Sciences, Inc. ^(a),(b)	4,535		168,430
CEL-SCI Corp. ^(a)	4,873		19,151
Celldex Therapeutics, Inc. ^(a)	5,266		179,360
Century Therapeutics, Inc. ^(a)	6,161		77,567
Cerevel Therapeutics Holdings, Inc. ^(a)	16,784		587,608
Certara, Inc. ^(a)	17,702		380,239
ChemoCentryx, Inc. ^(a)	8,164		204,671
ChromaDex Corp. ^(a)	7,724		19,001
Clearside Biomedical, Inc. ^(a)	6,738		15,430
Cortexyme, Inc. ^(a)	3,367		20,842
CRISPR Therapeutics AG ^(a)	8,815		553,318

See accompanying notes.


	Schedule of Investments
	Principal Healthcare Innovators ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value

Biotechnology (continued)
Cullinan Oncology, Inc. ^(a)		4,936	$	51,680
Curis, Inc. ^(a)		10,381		24,707
CytomX Therapeutics, Inc. ^(a)		7,384		19,715
Deciphera Pharmaceuticals, Inc. ^(a)		6,581		61,006
Denali Therapeutics, Inc. ^(a)		14,084		453,082
Dynavax Technologies Corp. ^(a)		13,001		140,931
Editas Medicine, Inc. ^(a)		7,735		147,120
Epizyme, Inc. ^(a)		11,586		13,324
Esperion Therapeutics, Inc. ^(a),(b)		3,203		14,862
Evolus, Inc. ^(a)		6,185		69,396
Fate Therapeutics, Inc. ^(a)		11,031		427,672
FibroGen, Inc. ^(a)		10,497		126,174
Forma Therapeutics Holdings, Inc. ^(a)		5,366		49,904
Forte Biosciences, Inc. ^(a)		1,590		2,321
Generation Bio Co. ^(a)		6,437		47,248
Global Blood Therapeutics, Inc. ^(a)		7,078		245,182
Gossamer Bio, Inc. ^(a)		8,611		74,743
Guardant Health, Inc. ^(a)		11,691		774,412
Homology Medicines, Inc. ^(a)		6,470		19,669
Humanigen, Inc. ^(a)		6,729		20,254
iBio, Inc. ^(a)		24,686		10,571
Ideaya Biosciences, Inc. ^(a)		4,350		48,676
IGM Biosciences, Inc. ^(a)		2,911		77,811
ImmunityBio, Inc. ^(a),(b)		45,568		255,636
ImmunoGen, Inc. ^(a)		22,935		109,171
Immunome, Inc. ^(a)		1,331		7,560
Immunovant, Inc. ^(a)		13,034		71,817
Impel Neuropharma, Inc. ^(a),(b)		2,210		14,078
Infinity Pharmaceuticals, Inc. ^(a)		10,053		11,460
Inmune Bio, Inc. ^(a)		2,010		16,924
Innoviva, Inc. ^(a)		7,871		152,304
Inovio Pharmaceuticals, Inc. ^(a)		23,837		85,575
Insmed, Inc. ^(a)		13,413		315,205
Intercept Pharmaceuticals, Inc. ^(a),(b)		3,759		61,159
Intra-Cellular Therapies, Inc. ^(a)		9,424		576,655
Ionis Pharmaceuticals, Inc. ^(a)		16,337		605,122
Iovance Biotherapeutics, Inc. ^(a)		17,641		293,723
iTeos Therapeutics, Inc. ^(a)		3,990		128,398
IVERIC bio, Inc. ^(a)		11,782		198,291
Janux Therapeutics, Inc. ^(a),(b)		4,716		67,627
Karuna Therapeutics, Inc. ^(a)		3,430		434,890
Karyopharm Therapeutics, Inc. ^(a)		8,554		63,043
Keros Therapeutics, Inc. ^(a)		2,646		143,889
Kiniksa Pharmaceuticals Ltd., Class A ^(a)		3,694		36,718
Kodiak Sciences, Inc. ^(a)		5,855		45,201
Krystal Biotech, Inc. ^(a)		2,511		167,082
Kymera Therapeutics, Inc. ^(a)		5,808		245,795
Lexicon Pharmaceuticals, Inc. ^(a)		16,373		34,220
MacroGenics, Inc. ^(a)		6,927		61,027
Mersana Therapeutics, Inc. ^(a)		8,132		32,447
Mirati Therapeutics, Inc. ^(a)		5,962		490,196
Mustang Bio, Inc. ^(a)		10,257		10,360
Myriad Genetics, Inc. ^(a)		8,847		222,944
Nektar Therapeutics ^(a)		20,831		112,279
NeoGenomics, Inc. ^(a)		14,303		173,781
NGM Biopharmaceuticals, Inc. ^(a)		8,760		133,590
Nkarta, Inc. ^(a)		3,724		42,379
Novavax, Inc. ^(a)		8,600		633,390

See accompanying notes.


Schedule of Investments
Principal Healthcare Innovators ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Biotechnology (continued)
NRX Pharmaceuticals, Inc. ^(a),(b)	5,508	$	13,495
Nurix Therapeutics, Inc. ^(a)	5,035		70,540
Nuvation Bio, Inc. ^(a)	24,559		129,180
Olema Pharmaceuticals, Inc. ^(a)	4,477		19,072
Omeros Corp. ^(a),(b)	7,078		42,539
PDS Biotechnology Corp. ^(a)	3,222		19,944
Pieris Pharmaceuticals, Inc. ^(a)	7,557		22,898
Precigen, Inc. ^(a)	23,413		49,401
Precision BioSciences, Inc. ^(a)	6,756		20,808
Prelude Therapeutics, Inc. ^(a)	4,038		27,862
Prothena Corp. PLC ^(a)	5,107		186,763
Provention Bio, Inc. ^(a)	7,184		52,587
PTC Therapeutics, Inc. ^(a)	8,206		306,166
Radius Health, Inc. ^(a)	5,358		47,311
RAPT Therapeutics, Inc. ^(a)	3,337		73,381
Recursion Pharmaceuticals, Inc., Class A ^(a),(b)	18,019		129,016
REGENXBIO, Inc. ^(a)	4,833		160,407
Relay Therapeutics, Inc. ^(a)	10,547		315,672
Replimune Group, Inc. ^(a)	5,296		89,926
REVOLUTION Medicines, Inc. ^(a)	8,335		212,626
Rigel Pharmaceuticals, Inc. ^(a)	19,360		57,886
Rocket Pharmaceuticals, Inc. ^(a)	7,211		114,366
Rubius Therapeutics, Inc. ^(a)	10,177		56,075
Sage Therapeutics, Inc. ^(a)	6,865		227,231
Sana Biotechnology, Inc. ^(a)	21,381		176,607
Sangamo Therapeutics, Inc. ^(a)	16,467		95,673
Scholar Rock Holding Corp. ^(a)	3,902		50,297
Seagen, Inc. ^(a)	17,506		2,521,739
Seelos Therapeutics, Inc. ^(a)	11,595		9,714
Seer, Inc. ^(a)	6,435		98,069
Selecta Biosciences, Inc. ^(a)	13,038		16,037
Sesen Bio, Inc. ^(a)	22,209		13,385
Silverback Therapeutics, Inc. ^(a)	3,972		13,942
Sorrento Therapeutics, Inc. ^(a)	33,781		78,710
SpringWorks Therapeutics, Inc. ^(a)	5,712		322,385
Stoke Therapeutics, Inc. ^(a)	4,163		87,631
Surface Oncology, Inc. ^(a)	5,153		15,150
Sutro Biopharma, Inc. ^(a)	5,226		42,958
Syndax Pharmaceuticals, Inc. ^(a)	5,508		95,729
TCR2 Therapeutics, Inc. ^(a)	4,330		11,951
TG Therapeutics, Inc. ^(a)	16,184		153,910
Theravance Biopharma, Inc. ^(a)	8,326		79,597
TransMedics Group, Inc. ^(a)	3,136		84,484
Travere Therapeutics, Inc. ^(a)	6,879		177,272
Turning Point Therapeutics, Inc. ^(a)	5,599		150,333
Twist Bioscience Corp. ^(a)	5,726		282,750
Tyme Technologies, Inc. ^(a),(b)	19,514		6,830
Ultragenyx Pharmaceutical, Inc. ^(a)	7,846		569,776
Vaxart, Inc. ^(a),(b)	13,918		70,147
Veracyte, Inc. ^(a)	8,032		221,442
Verastem, Inc. ^(a)	20,485		28,884
Vericel Corp. ^(a)	5,287		202,069
Verve Therapeutics, Inc. ^(a)	5,434		124,004
Viking Therapeutics, Inc. ^(a)	8,860		26,580
Vir Biotechnology, Inc. ^(a)	15,115		388,758
Xencor, Inc. ^(a)	6,615		176,488
Zentalis Pharmaceuticals, Inc. ^(a)	5,241		241,820
		$	30,486,752

See accompanying notes.


	Schedule of Investments
	Principal Healthcare Innovators ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value

Chemicals — 0.21%
Codexis, Inc. ^(a)		7,329	$	151,124

Commercial Services — 1.42%
HealthEquity, Inc. ^(a)		9,666		651,875
Multiplan Corp. ^(a)		77,722		363,739
			$	1,015,614

Electronics — 0.05%
Fluidigm Corp. ^(a)		8,631		30,985

Engineering & Construction — 0.08%
908 Devices, Inc. ^(a)		3,131		59,520

Healthcare — Products — 22.97%
10X Genomics, Inc., Class A ^(a)		10,448		794,779
ABIOMED, Inc. ^(a)		5,225		1,730,729
Acutus Medical, Inc. ^(a)		3,162		4,395
Adaptive Biotechnologies Corp. ^(a)		16,015		222,288
Alphatec Holdings, Inc. ^(a)		11,348		130,502
AngioDynamics, Inc. ^(a)		4,356		93,828
Artivion, Inc. ^(a)		4,453		95,205
Asensus Surgical, Inc. ^(a)		26,551		16,642
AtriCure, Inc. ^(a)		5,331		350,087
Avanos Medical, Inc. ^(a)		5,451		182,609
Axonics, Inc. ^(a)		5,372		336,287
BioLife Solutions, Inc. ^(a)		4,617		104,944
Bionano Genomics, Inc. ^(a),(b)		31,630		81,605
Butterfly Network, Inc. ^(a)		18,984		90,364
Cardiovascular Systems, Inc. ^(a)		4,556		102,966
CareDx, Inc. ^(a)		5,968		220,756
Castle Biosciences, Inc. ^(a)		2,853		127,986
Cerus Corp. ^(a)		19,450		106,781
ClearPoint Neuro, Inc. ^(a)		2,536		26,400
Cutera, Inc. ^(a)		2,033		140,277
DermTech, Inc. ^(a)		3,357		49,281
Eargo, Inc. ^(a)		4,438		23,477
Exact Sciences Corp. ^(a)		19,805		1,384,766
Glaukos Corp. ^(a)		5,419		313,327
Haemonetics Corp. ^(a)		5,935		375,211
Inogen, Inc. ^(a)		2,562		83,060
Inspire Medical Systems, Inc. ^(a)		3,150		808,573
Insulet Corp. ^(a)		7,927		2,111,674
iRhythm Technologies, Inc. ^(a)		3,408		536,658
Lantheus Holdings, Inc. ^(a)		7,852		434,294
Lucira Health, Inc. ^(a)		4,384		15,651
Merit Medical Systems, Inc. ^(a)		6,531		434,442
MiMedx Group, Inc. ^(a)		12,681		59,728
NanoString Technologies, Inc. ^(a)		5,155		179,136
Natera, Inc. ^(a)		10,827		440,442
Nautilus Biotechnology, Inc. ^(a)		14,061		61,025
Nevro Corp. ^(a)		3,968		287,005
Novocure Ltd. ^(a)		11,959		990,803
OraSure Technologies, Inc. ^(a)		8,156		55,298
OrthoPediatrics Corp. ^(a)		2,224		120,074
Pacific Biosciences of California, Inc. ^(a)		22,652		206,133
PAVmed, Inc. ^(a),(b)		9,606		12,680
Progenity, Inc. ^(a),(b)		9,001		10,441
Pulmonx Corp. ^(a)		4,154		103,061
Quanterix Corp. ^(a)		4,141		120,876

See accompanying notes.


	Schedule of Investments
	Principal Healthcare Innovators ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value

Healthcare — Products (continued)
Quantum-Si, Inc. ^(a),(b)		13,196	$	61,757
Shockwave Medical, Inc. ^(a)		4,064		842,711
SI-BONE, Inc. ^(a)		3,767		85,134
Sientra, Inc. ^(a)		6,576		14,599
Silk Road Medical, Inc. ^(a)		3,933		162,394
SmileDirectClub, Inc. ^(a)		13,468		34,882
Surgalign Holdings, Inc. ^(a)		15,795		4,806
T2 Biosystems, Inc. ^(a),(b)		18,793		9,849
Tandem Diabetes Care, Inc. ^(a)		7,273		845,777
Varex Imaging Corp. ^(a)		4,466		95,081
ViewRay, Inc. ^(a)		18,623		73,002
			$	16,406,538

Healthcare — Services — 14.02%
23andMe Holding Co., Class A ^(a),(b)		10,535		40,349
Accolade, Inc. ^(a)		7,488		131,489
agilon health, Inc. ^(a)		45,137		1,144,223
American Well Corp., Class A ^(a)		23,872		100,501
ATI Physical Therapy, Inc. ^(a)		22,281		41,888
Brookdale Senior Living, Inc. ^(a)		21,215		149,566
Cano Health, Inc. ^(a)		19,618		124,574
CareMax, Inc. ^(a)		9,189		68,642
Centene Corp. ^(a)		47,768		4,021,588
Clover Health Investments Corp. ^(a)		26,725		94,874
Invitae Corp. ^(a)		25,315		201,761
LifeStance Health Group, Inc. ^(a),(b)		43,460		439,381
MEDNAX, Inc. ^(a)		9,784		229,728
Neuronetics, Inc. ^(a)		2,978		9,023
Oak Street Health, Inc. ^(a),(b)		27,891		749,710
Ontrak, Inc. ^(a)		2,117		4,795
OPKO Health, Inc. ^(a)		77,511		266,638
Personalis, Inc. ^(a)		5,034		41,228
Sema4 Holdings Corp. ^(a)		27,219		83,562
Surgery Partners, Inc. ^(a)		9,560		526,278
Teladoc Health, Inc. ^(a)		18,344		1,323,153
Tivity Health, Inc. ^(a)		5,623		180,892
Vapotherm, Inc. ^(a)		2,942		40,894
			$	10,014,737

Pharmaceuticals — 15.43%
Aclaris Therapeutics, Inc. ^(a)		6,935		119,559
Adamis Pharmaceuticals Corp. ^(a),(b)		16,872		9,634
AdaptHealth Corp. ^(a)		14,896		238,783
Aerie Pharmaceuticals, Inc. ^(a)		5,353		48,712
Agios Pharmaceuticals, Inc. ^(a)		6,685		194,600
Akebia Therapeutics, Inc. ^(a)		19,774		14,196
Alector, Inc. ^(a)		9,165		130,601
Alkermes PLC ^(a)		18,686		491,629
Amneal Pharmaceuticals, Inc. ^(a)		16,918		70,548
Arvinas, Inc. ^(a)		5,706		384,014
Athenex, Inc. ^(a)		12,387		10,275
Bioxcel Therapeutics, Inc. ^(a)		3,169		66,264
Chimerix, Inc. ^(a)		9,775		44,769
Citius Pharmaceuticals, Inc. ^(a),(b)		16,538		29,603
Clovis Oncology, Inc. ^(a),(b)		13,418		27,104
Coherus Biosciences, Inc. ^(a)		8,665		111,865
Cytokinetics, Inc. ^(a)		9,711		357,462

See accompanying notes.


	Schedule of Investments
	Principal Healthcare Innovators ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value

Pharmaceuticals (continued)
Elanco Animal Health, Inc. ^(a)		54,491	$	1,421,670
Enanta Pharmaceuticals, Inc. ^(a)		2,296		163,429
Fulcrum Therapeutics, Inc. ^(a)		4,565		107,962
G1 Therapeutics, Inc. ^(a),(b)		4,794		36,434
Galectin Therapeutics, Inc. ^(a)		6,719		10,818
Gritstone bio, Inc. ^(a)		5,604		23,088
Harmony Biosciences Holdings, Inc. ^(a)		6,650		323,522
Heron Therapeutics, Inc. ^(a)		11,546		66,043
Heska Corp. ^(a)		1,205		166,627
Intellia Therapeutics, Inc. ^(a)		8,483		616,460
Jaguar Health, Inc. ^(a),(b)		5,190		3,677
Kala Pharmaceuticals, Inc. ^(a)		7,365		10,164
KalVista Pharmaceuticals, Inc. ^(a)		2,766		40,771
Kura Oncology, Inc. ^(a)		7,508		120,729
Lyell Immunopharma, Inc. ^(a),(b)		27,123		136,971
Madrigal Pharmaceuticals, Inc. ^(a)		1,879		184,367
MannKind Corp. ^(a)		28,293		104,118
Marinus Pharmaceuticals, Inc. ^(a)		4,160		38,896
Morphic Holding, Inc. ^(a)		4,125		165,619
Ocugen, Inc. ^(a)		22,521		74,319
Ocular Therapeutix, Inc. ^(a)		8,680		42,966
Option Care Health, Inc. ^(a)		20,825		594,762
Oramed Pharmaceuticals, Inc. ^(a)		3,686		31,884
ORIC Pharmaceuticals, Inc. ^(a)		4,455		23,790
Outlook Therapeutics, Inc. ^(a),(b)		19,867		35,363
Passage Bio, Inc. ^(a)		6,127		18,994
Perrigo Co. PLC		15,462		594,205
PetIQ, Inc. ^(a)		3,277		79,959
PLx Pharma, Inc. ^(a),(b)		3,048		12,314
PMV Pharmaceuticals, Inc. ^(a)		5,130		106,807
Protagonist Therapeutics, Inc. ^(a)		5,390		127,635
Reata Pharmaceuticals, Inc., Class A ^(a)		3,567		116,855
Relmada Therapeutics, Inc. ^(a)		1,972		53,224
Revance Therapeutics, Inc. ^(a)		8,143		158,788
Rhythm Pharmaceuticals, Inc. ^(a)		5,688		65,526
Sarepta Therapeutics, Inc. ^(a)		9,224		720,579
Senseonics Holdings, Inc. ^(a),(b)		50,452		99,390
Seres Therapeutics, Inc. ^(a)		10,396		74,020
Spectrum Pharmaceuticals, Inc. ^(a)		18,595		23,988
Syros Pharmaceuticals, Inc. ^(a)		7,015		8,348
TherapeuticsMD, Inc. ^(a)		48,021		18,248
Tonix Pharmaceuticals Holding Corp. ^(a)		40,512		9,326
uniQure NV ^(a)		5,226		94,434
Vaxcyte, Inc. ^(a)		5,912		142,775
Viatris, Inc.		139,185		1,514,333
Xeris Biopharma Holdings, Inc. ^(a)		7,539		19,300
Y-mAbs Therapeutics, Inc. ^(a)		4,941		58,699
Zynerba Pharmaceuticals, Inc. ^(a)		4,673		9,580
			$	11,021,394

Retail — 0.11%
OptimizeRx Corp. ^(a)		1,998		75,345

Software — 2.84%
1Life Healthcare, Inc. ^(a)		20,633		228,614
Evolent Health, Inc., Class A ^(a)		10,172		328,555

See accompanying notes.


		Schedule of Investments
		Principal Healthcare Innovators ETF
		March 31, 2022 (unaudited)

COMMON STOCKS (continued)				Shares Held		Value

Software (continued)
Health Catalyst, Inc. ^(a)				5,282	$	138,019
Hims & Hers Health, Inc. ^(a)				22,080		117,686
Outset Medical, Inc. ^(a)				5,249		238,305
Phreesia, Inc. ^(a)				5,763		151,913
Privia Health Group, Inc. ^(a)				12,307		328,966
Sharecare, Inc. ^(a)				37,830		93,440
Signify Health, Inc., Class A ^(a)				19,588		355,522
Tabula Rasa HealthCare, Inc. ^(a)				2,829		16,295
Talkspace, Inc. ^(a),(b)				17,249		30,013
					$	2,027,328
TOTAL COMMON STOCKS					$	71,289,337
INVESTMENT COMPANIES — 2.83%				Shares Held		Value

Money Market Funds — 2.83%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(a),(c),(d),(e)}				1,870,512	$	1,870,512
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(e)				150,687		150,687
TOTAL INVESTMENT COMPANIES					$	2,021,199
Total Investments					$	73,310,536
Other Assets and Liabilities — (2.65)%						(1,889,354	)

Total Net Assets — 100.00%					$	71,421,182

^(a)	Non-income producing security.
^(b)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $1,760,056 or
	2.46% of net assets.
^(c)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of
	these securities totaled $1,870,512 or 2.62% of net assets.
^(d)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate
	as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(e)	Current yield shown is as of period end.

	Portfolio Summary (unaudited)
Sector		Percent
Consumer, Non-cyclical		96.53	%
Technology		2.84	%
Money Market Funds		2.83	%
Basic Materials		0.21	%
Industrial		0.13	%
Consumer, Cyclical		0.11	%
Other Assets and Liabilities		(2.65	)%
TOTAL NET ASSETS		100.00	%

See accompanying notes.


			Schedule of Investments
			Principal Healthcare Innovators ETF
			March 31, 2022 (unaudited)

			June 30, 2021		Purchases		Sales		March 31, 2022
Affiliated Securities			Value		Cost		Proceeds		Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	6,534,128	$	42,674,669	$	47,338,285	$	1,870,512
		$	6,534,128	$	42,674,669	$	47,338,285	$	1,870,512

							Realized Gain
					Realized		from		Change in
					Gain/(Loss) on		Capital Gain		Unrealized
			Income ^(a)		Investments		Distributions		Gain/(Loss)
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$	— $		—	$	—
		$	—	$	— $		—	$	—

^(a)Amount excludes earnings from securities lending collateral.

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS — 98.08%	Shares Held		Value

Advertising — 0.24%
Hakuhodo DY Holdings, Inc.	2,700	$	34,266
Publicis Groupe SA	714		43,648
WPP PLC	1,821		23,993
		$	101,907

Aerospace & Defense — 0.75%
Airbus SE ^(a)	510		62,264
BAE Systems PLC	11,963		112,741
Dassault Aviation SA	240		38,152
Elbit Systems Ltd.	166		36,414
Rolls-Royce Holdings PLC ^(a)	16,631		22,087
Thales SA	402		50,675
		$	322,333

Agriculture — 1.06%
British American Tobacco PLC	6,164		258,669
Imperial Brands PLC	4,390		92,876
Japan Tobacco, Inc.	4,300		73,733
Swedish Match AB	3,858		29,084
		$	454,362

Airlines — 0.09%
Singapore Airlines Ltd. ^(a)	9,900		40,174

Apparel — 1.23%
adidas AG	187		43,835
Burberry Group PLC	918		20,187
Gildan Activewear, Inc.	1,601		60,050
Hermes International	34		48,577
Kering SA	70		44,581
LVMH Moet Hennessy Louis Vuitton SE	404		290,233
Puma SE	235		20,132
		$	527,595

Auto Manufacturers — 2.28%
Bayerische Motoren Werke AG	234		18,198
Bayerische Motoren Werke AG	401		34,868
Ferrari NV	146		32,093
Hino Motors Ltd.	5,200		30,754
Honda Motor Co. Ltd.	3,800		108,844
Isuzu Motors Ltd.	3,200		41,741
Mazda Motor Corp.	5,000		37,334
Mercedes-Benz Group AG	1,608		113,508
Stellantis NV	2,175		35,610
Toyota Motor Corp.	24,900		454,577
Volkswagen AG	73		18,267
Volvo AB, Class A	854		16,440
Volvo AB, Class B	1,722		32,343
		$	974,577

Auto Parts & Equipment — 0.44%
Aisin Corp.	1,200		41,350
Bridgestone Corp.	2,100		82,075
Cie Generale des Etablissements Michelin SCA	234		31,827
NGK Insulators Ltd.	2,300		33,119
		$	188,371

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Banks — 10.09%
ABN AMRO Bank NV ^(b)	1,405	$	18,095
Australia & New Zealand Banking Group Ltd.	3,395		70,117
Banco Bilbao Vizcaya Argentaria SA	6,678		38,489
Banco Santander SA	15,435		52,932
Bank Hapoalim BM	7,248		72,114
Bank Leumi Le-Israel BM	4,617		49,974
Bank of Montreal	1,890		222,404
Bank of Nova Scotia	3,457		247,768
Barclays PLC	33,844		65,933
BNP Paribas SA	970		55,724
BOC Hong Kong Holdings Ltd.	15,000		56,873
CaixaBank SA	7,204		24,522
Canadian Imperial Bank of Commerce	1,415		171,760
Commerzbank AG ^(a)	2,619		20,069
Commonwealth Bank of Australia	3,400		269,102
Credit Agricole SA	2,074		24,977
Danske Bank A/S	2,447		40,977
DBS Group Holdings Ltd.	4,200		111,031
Deutsche Bank AG ^(a)	2,698		34,354
DNB Bank ASA	1,274		28,956
Erste Group Bank AG	649		23,757
FinecoBank Banca Fineco SpA	1,296		19,821
Hang Seng Bank Ltd.	2,909		56,150
HSBC Holdings PLC	22,663		156,418
ING Groep NV	3,891		40,939
Intesa Sanpaolo SpA	16,826		38,782
Israel Discount Bank Ltd., Class A	5,580		34,902
KBC Group NV	366		26,472
Lloyds Banking Group PLC	143,237		88,540
Macquarie Group Ltd.	1,104		167,926
Mediobanca Banca di Credito Finanziario SpA	3,543		36,137
Mitsubishi UFJ Financial Group, Inc.	27,900		174,243
Mizrahi Tefahot Bank Ltd.	1,492		58,537
Mizuho Financial Group, Inc.	900		11,585
National Australia Bank Ltd.	6,775		164,006
National Bank of Canada	1,393		106,780
NatWest Group PLC	8,802		24,964
Nordea Bank Abp	3,527		36,499
Oversea-Chinese Banking Corp. Ltd.	8,900		81,294
Raiffeisen Bank International AG	2,013		28,838
Royal Bank of Canada	3,714		408,907
Skandinaviska Enskilda Banken AB, Class A	4,486		48,880
Societe Generale SA	1,099		29,738
Standard Chartered PLC	7,326		49,101
Sumitomo Mitsui Financial Group, Inc.	1,300		41,721
Svenska Handelsbanken AB, Class A	3,302		30,518
Swedbank AB	1,518		22,764
Toronto-Dominion Bank	4,827		382,986
UBS Group AG	3,133		61,521
UniCredit SpA	2,790		30,417
United Overseas Bank Ltd.	3,400		80,325
Westpac Banking Corp.	4,505		81,715
		$	4,321,354

Beverages — 2.11%
Anheuser-Busch InBev SA	1,674		100,482
Carlsberg AS, Class B	175		21,602

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Beverages (continued)
Coca-Cola HBC AG	773	$	16,242
Davide Campari-Milano NV	3,653		42,654
Diageo PLC	6,412		325,427
Endeavour Group Ltd.	7,922		43,215
Heineken Holding NV	578		45,462
Heineken NV	742		71,068
JDE Peet's NV	502		14,400
Pernod Ricard SA	711		156,758
Remy Cointreau SA	194		40,133
Treasury Wine Estates Ltd.	2,796		24,228
		$	901,671

Biotechnology — 0.25%
Bachem Holding AG, Class B	52		28,756
CSL Ltd.	391		78,457
		$	107,213

Building Materials — 1.27%
AGC, Inc.	1,100		44,320
Cie de Saint-Gobain	1,088		65,319
Daikin Industries Ltd.	600		110,448
Geberit AG	107		66,258
Holcim Ltd.	833		40,827
Investment AB Latour, Class B	576		18,440
James Hardie Industries PLC	705		21,419
Kingspan Group PLC	470		46,295
Nibe Industrier AB	2,340		26,144
Rinnai Corp.	400		30,130
ROCKWOOL International A/S, Class B	53		17,593
Sika AG	132		43,912
Xinyi Glass Holdings Ltd.	6,000		14,553
		$	545,658

Chemicals — 3.05%
Air Liquide SA	554		97,396
Arkema SA	304		36,573
Asahi Kasei Corp.	6,100		53,239
BASF SE	808		46,266
Brenntag SE	395		32,047
Chr Hansen Holding A/S	269		19,871
Covestro AG ^(b)	386		19,574
Croda International PLC	342		35,402
EMS-Chemie Holding AG	48		46,829
Evonik Industries AG	882		24,569
Fuchs Petrolub SE	975		35,356
Givaudan SA	23		95,256
ICL Group Ltd.	3,234		38,744
Koninklijke DSM NV	468		84,130
Mitsubishi Chemical Holdings Corp.	7,100		47,654
Mitsubishi Gas Chemical Co., Inc.	1,900		32,478
Mitsui Chemicals, Inc.	1,400		35,535
Nippon Sanso Holdings Corp.	1,600		30,636
Novozymes A/S, Class B	816		56,187
Nutrien Ltd.	1,092		112,873
Shin-Etsu Chemical Co. Ltd.	800		123,476
Sumitomo Chemical Co. Ltd.	9,600		44,317
Symrise AG	475		57,197
Toray Industries, Inc.	9,100		47,750

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Chemicals (continued)
Tosoh Corp.	2,300	$	34,271
Umicore SA	468		20,378
		$	1,308,004

Commercial Services — 2.69%
Adyen NV ^(a),(b)	20		40,024
Ashtead Group PLC	522		33,141
Atlantia SpA ^(a)	2,413		50,451
Brambles Ltd.	3,871		28,706
Bureau Veritas SA	1,512		43,389
Dai Nippon Printing Co. Ltd.	1,600		37,825
Edenred	630		31,307
Experian PLC	3,312		128,392
Intertek Group PLC	714		48,998
Nuvei Corp. ^(a),(b)	288		21,655
Persol Holdings Co. Ltd.	1,800		40,868
Randstad NV	306		18,496
Recruit Holdings Co. Ltd.	3,200		142,310
RELX PLC	6,064		189,829
Rentokil Initial PLC	3,367		23,265
Ritchie Bros Auctioneers, Inc.	414		24,453
Secom Co. Ltd.	900		65,560
Securitas AB, Class B	1,328		15,035
SGS SA	21		58,542
Sohgo Security Services Co. Ltd.	900		29,571
TOPPAN, Inc.	2,000		35,584
Transurban Group	4,474		45,364
		$	1,152,765

Computers — 1.36%
Bechtle AG	319		18,068
Capgemini SE	343		76,837
CGI, Inc. ^(a)	738		58,791
Check Point Software Technologies Ltd. ^(a)	565		78,117
Computershare Ltd.	1,224		22,623
Fujitsu Ltd.	100		15,127
Itochu Techno-Solutions Corp.	1,400		36,110
Logitech International SA	296		22,167
NEC Corp.	1,200		50,764
NTT Data Corp.	3,000		59,586
Otsuka Corp.	1,100		39,260
SCSK Corp.	1,900		32,790
Teleperformance	184		70,489
		$	580,729

Distribution/Wholesale — 1.95%
Bunzl PLC	1,896		73,923
Ferguson PLC	813		110,858
IMCD NV	235		40,360
ITOCHU Corp.	3,600		122,543
Marubeni Corp.	6,000		70,281
Mitsubishi Corp.	3,600		136,057
Mitsui & Co. Ltd.	3,500		95,679
Sumitomo Corp.	4,100		71,365
Toromont Industries Ltd.	659		62,471
Toyota Tsusho Corp.	1,200		49,877
		$	833,414

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Diversified Financial Services — 2.63%
Amundi SA ^(b)	251	$	17,271
ASX Ltd.	1,199		73,392
Brookfield Asset Management, Inc., Class A	4,103		231,972
Daiwa Securities Group, Inc.	8,400		47,796
Deutsche Boerse AG	720		129,830
EQT AB	1,173		46,422
Euronext NV ^(b)	459		41,992
Futu Holdings Ltd., ADR ^(a)	523		17,029
Hargreaves Lansdown PLC	1,195		15,824
Hong Kong Exchanges & Clearing Ltd.	2,700		128,015
IGM Financial, Inc.	1,347		47,592
Julius Baer Group Ltd.	407		23,732
Mitsubishi HC Capital, Inc.	6,200		29,029
Onex Corp.	620		41,550
Partners Group Holding AG	27		33,704
SBI Holdings, Inc.	1,700		43,289
Schroders PLC	579		24,575
Singapore Exchange Ltd.	5,700		41,929
St. James's Place PLC	1,146		21,806
TMX Group Ltd.	375		38,569
Tokyo Century Corp.	827		30,671
		$	1,125,989

Electric — 2.85%
Algonquin Power & Utilities Corp.	1,601		24,832
Brookfield Renewable Corp., Class A	504		22,012
Canadian Utilities Ltd., Class A	1,177		36,078
CLP Holdings Ltd.	5,648		55,050
E.ON SE	9,115		106,300
EDP - Energias de Portugal SA	6,299		31,113
Elia Group SA	254		38,832
Emera, Inc.	1,061		52,594
Endesa SA	1,197		26,186
Enel SpA	9,879		66,315
Engie SA	2,374		31,342
Fortis, Inc.	1,387		68,598
HK Electric Investments & HK Electric Investments Ltd.	33,000		32,228
Hydro One Ltd. ^(b)	1,611		43,402
Iberdrola SA	6,725		73,800
National Grid PLC	7,956		122,532
Northland Power, Inc.	773		25,698
Origin Energy Ltd.	4,293		20,014
Power Assets Holdings Ltd.	7,500		48,878
Red Electrica Corp. SA	2,180		44,880
RWE AG	774		33,847
SSE PLC	4,530		104,050
Terna - Rete Elettrica Nazionale	8,917		76,804
Uniper SE	632		16,360
Verbund AG	178		18,805
		$	1,220,550

Electrical Components & Equipment — 0.61%
ABB Ltd.	5,183		169,224
Legrand SA	731		69,853
Prysmian SpA	594		20,344
		$	259,421

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Electronics — 1.43%
Halma PLC	1,523	$	50,217
Hoya Corp.	900		103,721
Ibiden Co. Ltd.	800		39,757
Kyocera Corp.	1,200		67,837
Murata Manufacturing Co. Ltd.	1,800		120,015
Nidec Corp.	1,000		80,072
Sartorius AG	47		20,886
Shimadzu Corp.	1,249		43,449
TDK Corp.	1,700		62,280
Venture Corp. Ltd.	1,774		22,997
		$	611,231

Engineering & Construction — 1.54%
ACS Actividades de Construccion y Servicios SA	918		24,881
Aena SME SA ^(a),(b)	133		22,224
Aeroports de Paris ^(a)	109		16,399
Auckland International Airport Ltd. ^(a)	4,801		26,053
Bouygues SA	729		25,508
Cellnex Telecom SA ^(b)	816		39,457
CK Infrastructure Holdings Ltd.	6,000		40,175
Eiffage SA	430		44,353
Ferrovial SA	1,817		48,503
Infrastrutture Wireless Italiane SpA ^(b)	2,053		23,086
Kajima Corp.	3,300		40,416
Keppel Corp. Ltd.	8,800		41,684
Lendlease Corp. Ltd.	2,956		24,774
Singapore Technologies Engineering Ltd.	12,900		39,214
Skanska AB, Class B	803		18,054
Vinci SA	1,009		103,796
WSP Global, Inc.	607		80,556
		$	659,133

Entertainment — 0.68%
Aristocrat Leisure Ltd.	919		25,238
Entain PLC ^(a)	1,045		22,562
Evolution AB ^(b)	236		24,299
Genting Singapore Ltd.	37,700		22,670
La Francaise des Jeux SAEM ^(b)	911		36,240
Oriental Land Co. Ltd.	500		96,558
Tabcorp Holdings Ltd.	16,284		65,070
		$	292,637

Environmental Control — 0.06%
GFL Environmental, Inc.	756		24,588

Food — 5.24%
Barry Callebaut AG	12		28,180
Carrefour SA	2,431		52,831
Chocoladefabriken Lindt & Spruengli AG	1		120,989
Chocoladefabriken Lindt & Spruengli AG	7		83,480
Coles Group Ltd.	4,380		58,701
Danone SA	873		48,317
Empire Co. Ltd., Class A	1,621		57,493
Etablissements Franz Colruyt NV	517		21,447
George Weston Ltd.	554		68,223
J Sainsbury PLC	11,526		38,262
Jeronimo Martins SGPS SA	2,624		63,078
Kerry Group PLC, Class A	527		58,941

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Food (continued)
Kesko Oyj, Class B	663	$	18,343
Kobe Bussan Co. Ltd.	1,200		37,210
Koninklijke Ahold Delhaize NV	2,736		88,122
Loblaw Cos. Ltd.	901		80,850
Metro, Inc.	1,332		76,671
Mowi ASA	832		22,492
Nestle SA	6,569		854,493
Nisshin Seifun Group, Inc.	2,400		33,632
Orkla ASA	2,829		25,180
Saputo, Inc.	913		21,625
Seven & i Holdings Co. Ltd.	1,700		81,174
Tesco PLC	21,185		76,810
Toyo Suisan Kaisha Ltd.	900		32,307
WH Group Ltd. ^(b)	34,000		21,485
Wilmar International Ltd.	7,200		25,021
Woolworths Group Ltd.	1,721		47,984
		$	2,243,341

Food Service — 0.13%
Compass Group PLC	1,733		37,563
Sodexo SA	218		17,798
		$	55,361

Forest Products & Paper — 0.27%
Mondi PLC	1,061		20,788
Oji Holdings Corp.	8,000		39,888
Smurfit Kappa Group PLC	503		22,508
West Fraser Timber Co. Ltd.	397		32,665
		$	115,849

Gas — 0.60%
AltaGas Ltd.	1,671		37,426
Enagas SA	1,721		38,363
Hong Kong & China Gas Co. Ltd.	40,250		48,763
Naturgy Energy Group SA	1,953		58,679
Snam SpA	12,692		73,460
		$	256,691

Hand/Machine Tools — 0.42%
Disco Corp.	200		56,514
Fuji Electric Co. Ltd.	900		45,540
Schindler Holding AG	110		23,689
Schindler Holding AG	94		20,131
Techtronic Industries Co. Ltd.	2,000		32,400
		$	178,274

Healthcare — Products — 1.95%
Alcon, Inc.	1,230		98,102
Carl Zeiss Meditec AG	123		19,995
Cochlear Ltd.	132		22,257
Coloplast A/S, Class B	408		62,164
Demant A/S ^(a)	415		18,886
DiaSorin SpA	121		18,994
EssilorLuxottica SA	562		103,391
Fisher & Paykel Healthcare Corp. Ltd.	1,096		18,496
Getinge AB	999		40,056
Inmode Ltd. ^(a)	770		28,421

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Healthcare — Products (continued)
Lifco AB	733	$	18,780
Olympus Corp.	4,000		76,852
QIAGEN NV ^(a)	1,011		49,803
Sartorius Stedim Biotech	60		24,725
Siemens Healthineers AG ^(b)	1,401		87,164
Smith & Nephew PLC	1,958		31,380
Sonova Holding AG	146		61,241
Straumann Holding AG	34		54,695
		$	835,402

Healthcare — Services — 0.67%
BioMerieux	153		16,374
Eurofins Scientific SE	238		23,672
Fresenius Medical Care AG & Co. KGaA	485		32,600
Fresenius SE & Co. KGaA	685		25,268
Lonza Group AG	100		72,745
Medibank Pvt Ltd.	10,728		24,725
Orpea SA	359		15,640
Ramsay Health Care Ltd.	560		27,301
Sonic Healthcare Ltd.	1,906		50,604
		$	288,929

Holding Companies — Diversified — 0.31%
CK Hutchison Holdings Ltd.	9,000		66,122
Jardine Matheson Holdings Ltd.	494		27,170
Swire Pacific Ltd., Class A	6,500		39,747
		$	133,039

Home Builders — 0.56%
Barratt Developments PLC	2,522		17,307
Berkeley Group Holdings PLC	458		22,502
Daiwa House Industry Co. Ltd.	2,300		60,475
Iida Group Holdings Co. Ltd.	1,600		27,797
Open House Group Co. Ltd.	800		35,617
Persimmon PLC	930		26,279
Sekisui House Ltd.	2,600		50,637
		$	240,614

Home Furnishings — 0.95%
GN Store Nord AS	367		18,159
Rational AG	23		15,953
SEB SA	272		38,094
Sharp Corp.	3,100		29,258
Sony Group Corp.	2,900		303,245
		$	404,709

Household Products — 0.95%
Beiersdorf AG	284		29,909
Essity AB, Class B	1,321		31,218
L'Oreal SA	503		202,462
Unilever PLC	3,147		142,832
		$	406,421

Household Products/Wares — 0.34%
Henkel AG & Co. KGaA	360		23,875
Reckitt Benckiser Group PLC	1,567		120,051
		$	143,926

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Insurance — 5.74%
Admiral Group PLC	518	$	17,440
Aegon NV	4,291		22,795
AIA Group Ltd.	24,200		254,719
Allianz SE	453		108,520
Assicurazioni Generali SpA	3,279		75,341
Aviva PLC	11,329		67,283
AXA SA	4,373		128,512
Baloise Holding AG	241		43,059
CNP Assurances	667		16,086
Fairfax Financial Holdings Ltd.	148		80,743
Gjensidige Forsikring ASA	2,174		54,005
Great-West Lifeco, Inc.	1,475		43,466
Hannover Rueck SE	117		19,978
iA Financial Corp., Inc.	1,017		61,834
Insurance Australia Group Ltd.	12,943		42,421
Intact Financial Corp.	726		107,272
Japan Post Holdings Co. Ltd.	9,000		66,417
M&G PLC	6,390		18,568
Manulife Financial Corp.	4,756		101,424
MS&AD Insurance Group Holdings, Inc.	1,700		55,550
Muenchener Rueckversicherungs-Gesellschaft AG in Muenchen	149		40,054
NN Group NV	485		24,605
Phoenix Group Holdings PLC	2,853		23,012
Power Corp. of Canada	2,761		85,470
QBE Insurance Group Ltd.	5,150		44,318
Sampo Oyj, Class A	1,483		72,808
Sompo Holdings, Inc.	1,300		57,461
Sun Life Financial, Inc.	2,196		122,610
Suncorp Group Ltd.	5,799		48,254
Swiss Life Holding AG	100		64,304
Swiss Re AG	834		79,533
T&D Holdings, Inc.	3,400		46,668
Tokio Marine Holdings, Inc.	1,900		111,247
Tryg A/S	1,179		28,799
Zurich Insurance Group AG	453		223,939
		$	2,458,515

Internet — 1.04%
Auto Trader Group PLC ^(b)	4,913		40,841
CyberAgent, Inc.	2,900		36,351
MonotaRO Co. Ltd.	1,800		38,945
Prosus NV	839		45,085
Shopify, Inc., Class A ^(a)	268		181,247
Trend Micro, Inc.	700		41,170
United Internet AG	651		22,455
ZOZO, Inc.	1,400		37,777
		$	443,871

Investment Companies — 0.48%
Eurazeo SE	196		16,565
Groupe Bruxelles Lambert SA	271		28,217
Industrivarden AB, Class A	795		22,728
Investor AB, Class A	947		22,198
Investor AB, Class B	1,826		40,036
L E Lundbergforetagen AB, Class B	329		16,817
Sofina SA	104		37,989

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Investment Companies (continued)
Wendel SE	215	$	22,024
		$	206,574

Iron & Steel — 0.62%
ArcelorMittal SA	1,665		53,968
BlueScope Steel Ltd.	1,267		19,777
Fortescue Metals Group Ltd.	2,143		33,131
JFE Holdings, Inc.	3,200		45,290
Mineral Resources Ltd.	988		38,970
Nippon Steel Corp.	3,400		60,632
voestalpine AG	509		15,214
		$	266,982

Leisure Time — 0.27%
Shimano, Inc.	300		69,381
Yamaha Motor Co. Ltd.	2,100		47,541
		$	116,922

Lodging — 0.13%
City Developments Ltd.	6,700		38,905
Crown Resorts Ltd. ^(a)	1,682		16,060
		$	54,965

Machinery — Construction & Mining — 0.66%
Epiroc AB, Class A	1,076		23,139
Epiroc AB, Class B	1,006		18,248
Hitachi Construction Machinery Co. Ltd.	1,400		36,742
Hitachi Ltd.	2,300		116,474
Mitsubishi Heavy Industries Ltd.	1,700		56,136
Sandvik AB	1,399		29,907
		$	280,646

Machinery — Diversified — 1.06%
CNH Industrial NV	3,005		47,853
FANUC Corp.	100		17,780
GEA Group AG	970		40,036
Husqvarna AB, Class B	1,492		15,656
Keyence Corp.	400		188,106
KION Group AG	215		14,271
Kone Oyj, Class B	1,066		56,121
Kornit Digital Ltd. ^(a)	205		16,951
Miura Co. Ltd.	1,300		32,409
Spirax-Sarco Engineering PLC	143		23,547
		$	452,730

Media — 0.89%
Bollore SE	3,336		17,544
Informa PLC ^(a)	2,897		22,902
Quebecor, Inc., Class B	1,555		37,067
Shaw Communications, Inc., Class B	2,538		78,770
Thomson Reuters Corp.	834		90,548
Vivendi SE	1,588		20,800
Wolters Kluwer NV	1,074		114,748
		$	382,379

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Metal Fabrication & Hardware — 0.19%
SKF AB, Class B	1,035	$	16,947
Tenaris SA	1,260		19,173
VAT Group AG ^(b)	116		44,489
		$	80,609

Mining — 3.24%
Agnico Eagle Mines Ltd.	550		33,656
Anglo American PLC	2,299		119,973
Antofagasta PLC	905		19,889
Barrick Gold Corp.	1,801		44,170
BHP Group Ltd.	11,867		459,544
Boliden AB	917		46,628
Cameco Corp.	765		22,280
First Quantum Minerals Ltd.	1,593		55,149
Franco-Nevada Corp.	730		116,167
Glencore PLC	8,415		55,272
Ivanhoe Mines Ltd., Class A ^(a)	2,016		18,803
Lundin Mining Corp.	1,817		18,415
Norsk Hydro ASA	2,357		23,051
Northern Star Resources Ltd.	2,398		19,272
Rio Tinto Ltd.	425		37,880
Rio Tinto PLC	918		73,333
South32 Ltd.	6,830		25,657
Sumitomo Metal Mining Co. Ltd.	1,100		55,687
Teck Resources Ltd., Class B	1,260		50,878
Wheaton Precious Metals Corp.	1,961		93,254
		$	1,388,958

Miscellaneous Manufacture — 0.13%
Orica Ltd.	1,550		18,500
Siemens AG	71		9,870
Smiths Group PLC	1,330		25,377
		$	53,747

Office & Business Equipment — 0.47%
Canon, Inc.	3,500		86,048
FUJIFILM Holdings Corp.	1,300		80,110
Seiko Epson Corp.	2,400		36,294
		$	202,452

Oil & Gas — 4.18%
Aker BP ASA	953		35,787
Ampol Ltd.	2,532		58,054
BP PLC	16,616		81,930
Canadian Natural Resources Ltd.	2,024		125,327
Cenovus Energy, Inc.	1,765		29,423
DCC PLC	552		42,971
ENEOS Holdings, Inc.	13,300		50,036
Eni SpA	6,303		92,695
Equinor ASA	1,029		38,711
Galp Energia SGPS SA	1,414		18,012
Idemitsu Kosan Co. Ltd.	1,400		38,812
Imperial Oil Ltd.	476		23,036
Inpex Corp.	4,700		55,594
Lundin Energy AB	481		20,427
OMV AG	757		36,336

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Oil & Gas (continued)
Parkland Corp.	838	$	24,782
Repsol SA	4,554		60,071
Shell PLC	18,095		501,201
Suncor Energy, Inc.	2,867		93,338
TotalEnergies SE	5,090		259,186
Tourmaline Oil Corp.	1,044		48,102
Woodside Petroleum Ltd.	2,302		55,295
		$	1,789,126

Packaging & Containers — 0.10%
CCL Industries, Inc., Class B	970		43,761

Pharmaceuticals — 8.32%
Amplifon SpA	419		18,791
Astellas Pharma, Inc.	400		6,279
AstraZeneca PLC	3,607		480,088
Bayer AG	3,061		210,285
Chugai Pharmaceutical Co. Ltd.	2,300		77,403
Daiichi Sankyo Co. Ltd.	4,100		90,258
GlaxoSmithKline PLC	13,859		299,887
Hikma Pharmaceuticals PLC	630		17,057
Ipsen SA	299		37,476
Medipal Holdings Corp.	1,700		28,138
Merck KGaA	311		65,317
Nippon Shinyaku Co. Ltd.	500		34,212
Novartis AG	4,609		405,261
Novo Nordisk A/S, Class B	3,937		438,485
Orion Oyj, Class B	379		17,253
Otsuka Holdings Co. Ltd.	1,700		59,096
Recordati Industria Chimica e Farmaceutica SpA	773		39,028
Roche Holding AG	1,639		649,977
Roche Holding AG	181		79,330
Sanofi	3,077		314,898
Takeda Pharmaceutical Co. Ltd.	3,800		109,187
UCB SA	704		84,461
		$	3,562,167

Pipelines — 1.25%
APA Group	5,792		46,245
Enbridge, Inc.	5,757		265,021
Keyera Corp.	1,556		39,443
Pembina Pipeline Corp.	1,719		64,585
TC Energy Corp.	2,160		121,827
		$	537,121

Private Equity — 0.23%
3i Group PLC	2,797		51,018
Capitaland Investment Ltd. ^(a)	15,500		45,630
		$	96,648

Real Estate — 1.81%
Azrieli Group Ltd.	453		40,004
CK Asset Holdings Ltd.	8,500		58,270
Daito Trust Construction Co. Ltd.	400		42,681
ESR Cayman Ltd. ^(a),(b)	19,600		60,927
Fastighets AB Balder, Class B ^(a)	574		37,935
FirstService Corp.	297		42,960
Hang Lung Properties Ltd.	11,000		22,187

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Real Estate (continued)
Henderson Land Development Co. Ltd.	10,000	$	41,617
Hongkong Land Holdings Ltd.	7,310		35,819
Hulic Co. Ltd.	4,200		37,984
LEG Immobilien SE	343		39,178
New World Development Co. Ltd.	6,000		24,396
REA Group Ltd.	169		17,132
Sagax AB, Class B	594		18,131
Sino Land Co. Ltd.	18,000		23,347
Sun Hung Kai Properties Ltd.	3,000		35,847
Swire Properties Ltd.	8,400		20,868
Swiss Prime Site AG	403		39,796
UOL Group Ltd.	4,600		23,893
Vonovia SE	1,806		84,531
Wharf Real Estate Investment Co. Ltd.	6,000		29,758
		$	777,261

REITs — 2.10%
Ascendas Real Estate Investment Trust	12,500		27,023
British Land Co. PLC	5,830		40,621
Canadian Apartment Properties REIT	869		37,293
CapitaLand Integrated Commercial Trust	26,017		43,190
Dexus	7,767		63,642
Gecina SA	183		23,139
Goodman Group	6,675		114,333
GPT Group	15,832		61,368
Klepierre SA	675		18,056
Land Securities Group PLC	5,762		59,464
Link REIT	6,900		59,017
Mapletree Commercial Trust	25,400		35,420
Mapletree Logistics Trust	27,100		36,990
Mirvac Group	13,893		25,886
RioCan Real Estate Investment Trust	2,493		50,313
Scentre Group	21,072		48,093
Segro PLC	5,385		95,181
Stockland	13,481		43,075
Vicinity Centres	12,839		17,918
		$	900,022

Retail — 2.18%
Alimentation Couche-Tard, Inc.	2,120		95,507
Canadian Tire Corp. Ltd., Class A	342		51,639
Chow Tai Fook Jewellery Group Ltd.	14,600		26,578
Cie Financiere Richemont SA	953		121,697
Cosmos Pharmaceutical Corp.	200		24,363
Dollarama, Inc.	1,457		82,631
Domino's Pizza Enterprises Ltd.	253		16,632
JD Sports Fashion PLC	8,823		17,183
Kingfisher PLC	10,194		34,201
Lawson, Inc.	700		26,881
McDonald's Holdings Co. Japan Ltd.	800		33,317
Moncler SpA	395		22,172
Next PLC	255		20,206
Nitori Holdings Co. Ltd.	400		50,468
Pan Pacific International Holdings Corp.	2,500		40,332
Pandora A/S	234		22,537
Reece Ltd.	1,162		16,573
Restaurant Brands International, Inc.	991		57,899
Ryohin Keikaku Co. Ltd.	2,212		26,001

See accompanying notes.


	Schedule of Investments
Principal International Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Retail (continued)
Swatch Group AG	306	$	16,690
Tsuruha Holdings, Inc.	400		25,497
Welcia Holdings Co. Ltd.	1,200		29,620
Wesfarmers Ltd.	1,464		55,225
Zalando SE ^(a),(b)	413		21,017
		$	934,866

Semiconductors — 2.70%
Advantest Corp.	800		63,545
ASM International NV	153		56,210
ASML Holding NV	969		653,893
Hamamatsu Photonics KK	900		48,423
Infineon Technologies AG	1,273		43,635
Lasertec Corp.	400		68,293
STMicroelectronics NV	1,537		67,315
Tokyo Electron Ltd.	300		155,865
		$	1,157,179

Shipbuilding — 0.03%
Wartsila Oyj Abp	1,548		14,224

Software — 1.93%
Capcom Co. Ltd.	1,400		34,132
Constellation Software, Inc.	74		126,495
Dassault Systemes SE	739		36,555
Koei Tecmo Holdings Co. Ltd.	1,000		32,980
Konami Holdings Corp.	700		44,562
Nemetschek SE	386		37,492
Open Text Corp.	1,151		48,806
Oracle Corp.	500		34,910
Sage Group PLC	4,908		45,209
SAP SE	2,037		227,867
Sinch AB ^(a),(b)	2,052		14,068
Square Enix Holdings Co. Ltd.	700		31,222
Temenos AG	193		18,589
TIS, Inc.	1,700		40,175
Ubisoft Entertainment SA ^(a)	343		15,159
WiseTech Global Ltd.	961		36,733
		$	824,954

Telecommunications — 4.13%
BCE, Inc.	971		53,826
BT Group PLC	12,115		28,997
Deutsche Telekom AG	7,046		131,979
Elisa Oyj	738		44,592
Hikari Tsushin, Inc.	300		34,426
HKT Trust & HKT Ltd.	30,000		41,209
KDDI Corp.	3,700		121,723
Koninklijke KPN NV	20,059		69,744
Nice Ltd. ^(a)	102		22,403
Nippon Telegraph & Telephone Corp.	3,700		107,742
Nokia Oyj ^(a)	15,008		82,772
Orange SA	5,604		66,359
Proximus SADP	1,927		35,920
Rogers Communications, Inc., Class B	1,151		65,148
Singapore Telecommunications Ltd.	28,800		56,098
SoftBank Corp.	9,000		105,569

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Telecommunications (continued)
SoftBank Group Corp.	2,800	$	127,856
Spark New Zealand Ltd.	7,488		23,768
Swisscom AG	98		58,860
Tele2 AB, Class B	4,313		65,275
Telefonica Deutschland Holding AG	13,378		36,540
Telefonica SA	22,248		108,009
Telenor ASA	1,891		27,225
Telia Co. AB	7,358		29,534
Telstra Corp. Ltd.	16,896		50,067
TELUS Corp.	2,683		70,093
Vodafone Group PLC	64,007		104,969
		$	1,770,703

Toys, Games & Hobbies — 0.35%
Nintendo Co. Ltd.	300		151,971

Transportation — 2.45%
AP Moller - Maersk A/S, Class A	14		41,537
AP Moller - Maersk A/S, Class B	17		51,500
Aurizon Holdings Ltd.	8,665		23,926
Canadian National Railway Co.	1,998		268,019
Canadian Pacific Railway Ltd.	1,923		158,713
Deutsche Post AG	909		43,793
DSV AS	206		39,842
Getlink SE	2,461		44,499
InPost SA ^(a)	2,612		16,644
Kuehne + Nagel International AG	76		21,639
Mitsui OSK Lines Ltd.	3,600		101,134
MTR Corp. Ltd.	4,500		24,329
Nippon Yusen KK	600		53,031
SG Holdings Co. Ltd.	2,200		41,781
SITC International Holdings Co. Ltd.	9,000		31,883
TFI International, Inc.	420		44,733
Yamato Holdings Co. Ltd.	2,300		43,321
		$	1,050,324

Water — 0.35%
Severn Trent PLC	1,159		46,863
United Utilities Group PLC	3,191		47,138
Veolia Environnement SA	1,699		54,675
		$	148,676
TOTAL COMMON STOCKS		$	42,004,585
PREFERRED STOCKS — 0.08%	Shares Held		Value

Auto Manufacturers — 0.08%
Volkswagen AG
2.84%, 09/09/2023	206	$	35,778
TOTAL PREFERRED STOCKS		$	35,778
INVESTMENT COMPANIES — 0.63%	Shares Held		Value

Money Market Fund — 0.63%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(c)	268,501	$	268,501
TOTAL INVESTMENT COMPANIES		$	268,501
Total Investments		$	42,308,864
Other Assets and Liabilities — 1.21%			518,863

Total Net Assets — 100.00%		$	42,827,727

See accompanying notes.


		Schedule of Investments
		Principal International Adaptive Multi-Factor ETF
		March 31, 2022 (unaudited)

^(a)	Non-income producing security.
^(b)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in
	transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these
	securities totaled $637,310 or 1.49% of net assets.
^(c)	Current yield shown is as of period end.

	Portfolio Summary (unaudited)
Location		Percent
Japan		19.60	%
Canada		15.29	%
United Kingdom		11.87	%
Switzerland		9.61	%
France		7.69	%
Australia		6.98	%
Germany		5.40	%
Netherlands		3.68	%
Hong Kong		3.44	%
Denmark		2.05	%
Sweden		2.00	%
Singapore		1.90	%
Italy		1.81	%
Spain		1.54	%
Israel		1.11	%
Belgium		0.92	%
Finland		0.80	%
Ireland		0.75	%
United States		0.68	%
Norway		0.60	%
Austria		0.29	%
Portugal		0.26	%
Luxembourg		0.23	%
New Zealand		0.16	%
Chile		0.05	%
Jordan		0.04	%
Poland		0.04	%
Other Assets and Liabilities		1.21	%
TOTAL NET ASSETS		100.00	%

See accompanying notes.


				Schedule of Investments
				Principal Investment Grade Corporate Active ETF
				March 31, 2022 (unaudited)

					Principal
BONDS — 98.76%					Amount		Value

Advertising — 0.18%
Omnicom Group, Inc.
2.60	%,	08/01/2031		$	816,000	$	754,328

Aerospace & Defense — 3.20%
Boeing Co.
2.20	%,	02/04/2026			5,005,000		4,731,809
2.70	%,	02/01/2027			2,818,000		2,702,870
2.80	%,	03/01/2024			336,000		335,587
3.25	%,	02/01/2028			1,296,000		1,248,428
3.50	%,	03/01/2039			386,000		332,223
4.88	%,	05/01/2025			371,000		382,750
5.71	%,	05/01/2040			2,502,000		2,795,861
5.81	%,	05/01/2050			596,000		688,223
						$	13,217,751

Agriculture — 1.97%
Altria Group, Inc.
2.35	%,	05/06/2025			18,000		17,483
3.40	%,	02/04/2041			938,000		769,766
5.80	%,	02/14/2039			381,000		410,642
5.95	%,	02/14/2049			120,000		129,906
BAT Capital Corp.
2.26	%,	03/25/2028			2,782,000		2,496,210
3.22	%,	08/15/2024			1,737,000		1,736,364
3.56	%,	08/15/2027			2,645,000		2,574,246
						$	8,134,617

Airlines — 3.78%
Continental Airlines 2012-1 Class A Pass Through Trust
4.15	%,	10/11/2025			735,194		737,485
Delta Air Lines, Inc./SkyMiles IP Ltd.
4.50	%,	10/20/2025	^(a)		3,441,583		3,461,577
4.75	%,	10/20/2028	^(a)		2,307,359		2,325,026
JetBlue 2019-1 Class AA Pass Through Trust
2.75	%,	11/15/2033			243,297		227,749
Southwest Airlines Co.
5.13	%,	06/15/2027			1,271,000		1,358,744
5.25	%,	05/04/2025			5,652,000		5,935,396
United Airlines 2014-2 Class A Pass Through Trust
3.75	%,	03/03/2028			520,362		507,768
United Airlines 2016-2 Class A Pass Through Trust
3.10	%,	04/07/2030			927,337		849,303
United Airlines 2019-2 Class AA Pass Through Trust
2.70	%,	11/01/2033			225,474		206,405
						$	15,609,453

Auto Manufacturers — 1.84%
Ford Motor Credit Co. LLC
2.90	%,	02/10/2029			2,184,000		1,945,332
General Motors Co.
5.00	%,	10/01/2028			2,865,000		2,987,526
6.25	%,	10/02/2043			1,099,000		1,246,049
General Motors Financial Co., Inc.
2.70	%,	06/10/2031			1,605,000		1,413,236
						$	7,592,143

See accompanying notes.


		Schedule of Investments
		Principal Investment Grade Corporate Active ETF
		March 31, 2022 (unaudited)

				Principal
BONDS (continued)				Amount		Value

Banks — 18.64%
Banco Santander SA
2.75	%,	12/03/2030	$	1,800,000	$	1,584,171
Bank of America Corp.
(6-month Secured Overnight Financing Rate + 1.06%),
2.09	%,	06/14/2029 ^(b)		2,413,000		2,204,139
(5-year Treasury Constant Maturity Rate + 1.20%),
2.48	%,	09/21/2036 ^(b)		2,302,000		1,979,195
(6-month Secured Overnight Financing Rate + 1.21%),
2.57	%,	10/20/2032 ^(b)		1,374,000		1,248,504
(6-month Secured Overnight Financing Rate + 1.93%),
2.68	%,	06/19/2041 ^(b)		817,000		689,841
(6-month Secured Overnight Financing Rate + 1.88%),
2.83	%,	10/24/2051 ^(b)		3,210,000		2,729,819
(3-month USD LIBOR + 1.19%),
2.88	%,	10/22/2030 ^(b)		607,000		575,607
(6-month Secured Overnight Financing Rate + 1.56%),
2.97	%,	07/21/2052 ^(b)		223,000		190,821
(5-year Treasury Constant Maturity Rate + 2.00%),
3.85	%,	03/08/2037 ^(b)		1,570,000		1,503,466
4.25	%,	10/22/2026		4,552,000		4,685,248
Barclays PLC
(1-year Treasury Constant Maturity Rate + 1.30%),
3.33	%,	11/24/2042 ^(b)		640,712		557,277
4.84	%,	05/09/2028		5,181,000		5,290,192
BPCE SA
(6-month Secured Overnight Financing Rate + 1.95%),
3.58	%,	10/19/2042 ^(a) ^,(b)		1,724,000		1,492,917
Citigroup, Inc.
(3-month USD LIBOR + 1.15%),
3.52	%,	10/27/2028 ^(b)		385,000		381,380
Credit Suisse Group AG
(6-month Secured Overnight Financing Rate + 0.98%),
1.31	%,	02/02/2027 ^(a) ^,(b)		2,983,000		2,667,983
(6-month Secured Overnight Financing Rate + 1.73%),
3.09	%,	05/14/2032 ^(a) ^,(b)		1,918,000		1,729,839
(5-year Treasury Constant Maturity Rate + 4.89%),
5.25	%,	02/11/2027 ^(a) ^,(b),(c),(d)		3,777,000		3,493,725
Deutsche Bank AG
(6-month US International Swaps and Derivative Association + 2.55%),
4.88	%,	12/01/2032 ^(b)		1,605,000		1,540,703
First Republic Bank
4.63	%,	02/13/2047		3,086,000		3,303,611
HSBC Holdings PLC
(6-month Secured Overnight Financing Rate + 1.29%),
1.59	%,	05/24/2027 ^(b)		5,769,000		5,265,483
(6-month Secured Overnight Financing Rate + 1.73%),
2.01	%,	09/22/2028 ^(b)		508,000		460,624
JPMorgan Chase & Co.
(3-month Term Secured Overnight Financing Rate + 0.70%),
1.04	%,	02/04/2027 ^(b)		6,444,000		5,904,750
(6-month Secured Overnight Financing Rate + 2.46%),
3.11	%,	04/22/2041 ^(b)		112,000		101,219
(3-month USD LIBOR + 1.38%),
3.96	%,	11/15/2048 ^(b)		528,000		539,342
5.50	%,	10/15/2040		723,000		867,708

See accompanying notes.


		Schedule of Investments
		Principal Investment Grade Corporate Active ETF
		March 31, 2022 (unaudited)

				Principal
BONDS (continued)				Amount		Value

Banks (continued)
Morgan Stanley
(6-month Secured Overnight Financing Rate + 0.88%),
1.59	%,	05/04/2027 ^(b)	$	1,436,000	$	1,334,161
(6-month Secured Overnight Financing Rate + 1.36%),
2.48	%,	09/16/2036 ^(b)		2,337,000		2,003,613
(6-month Secured Overnight Financing Rate + 1.43%),
2.80	%,	01/25/2052 ^(b)		2,055,000		1,709,694
(3-month USD LIBOR + 1.34%),
3.59	%,	07/22/2028 ^(b)		3,390,000		3,399,428
5.00	%,	11/24/2025		1,692,000		1,783,571
National Australia Bank Ltd.
2.33	%,	08/21/2030 ^(a)		2,205,000		1,918,101
Natwest Group PLC
(3-month USD LIBOR + 1.91%),
5.08	%,	01/27/2030 ^(b)		1,805,000		1,921,906
Standard Chartered PLC
(3-month USD LIBOR + 1.21%),
2.82	%,	01/30/2026 ^(a) ^,(b)		2,110,000		2,051,996
(5-year Treasury Constant Maturity Rate + 2.30%),
3.27	%,	02/18/2036 ^(a) ^,(b)		1,717,000		1,539,256
(5-year Treasury Constant Maturity Rate + 5.66%),
6.00	%,	07/26/2025 ^(a) ^,(b),(c),(d)		1,476,000		1,522,125
Sumitomo Mitsui Financial Group, Inc.
1.90	%,	09/17/2028		1,173,000		1,049,731
Wells Fargo & Co.
(6-month Secured Overnight Financing Rate + 2.10%),
2.39	%,	06/02/2028 ^(b)		4,423,000		4,182,389
Westpac Banking Corp.
(5-year Treasury Constant Maturity Rate + 1.53%),
3.02	%,	11/18/2036 ^(b)		796,000		707,284
(5-year Treasury Constant Maturity Rate + 2.00%),
4.11	%,	07/24/2034 ^(b)		795,000		783,608
					$	76,894,427

Beverages — 2.12%
Anheuser-Busch Cos. LLC/Anheuser-Busch InBev Worldwide, Inc.
3.65	%,	02/01/2026		1,180,000		1,205,975
4.90	%,	02/01/2046		1,510,000		1,679,339
Anheuser-Busch InBev Worldwide, Inc.
4.38	%,	04/15/2038		4,034,000		4,238,815
4.60	%,	04/15/2048		396,000		427,392
5.45	%,	01/23/2039		912,000		1,065,010
Constellation Brands, Inc.
2.88	%,	05/01/2030		147,000		137,885
					$	8,754,416

Biotechnology — 0.16%
Gilead Sciences, Inc.
4.50	%,	02/01/2045		627,000		668,070

Building Materials — 0.47%
Masco Corp.
1.50	%,	02/15/2028		2,179,000		1,917,713

Chemicals — 0.29%
International Flavors & Fragrances, Inc.
1.23	%,	10/01/2025 ^(a)		567,000		524,884

See accompanying notes.


		Schedule of Investments
			Principal Investment Grade Corporate Active ETF
			March 31, 2022 (unaudited)

				Principal
BONDS (continued)				Amount		Value

Chemicals (continued)
International Flavors & Fragrances, Inc. (continued)
1.83	%,	10/15/2027 ^(a)	$	739,000	$	671,734
					$	1,196,618

Commercial Services — 1.49%
CoStar Group, Inc.
2.80	%,	07/15/2030 ^(a)		4,781,000		4,369,692
PayPal Holdings, Inc.
3.25	%,	06/01/2050		1,945,000		1,773,031
					$	6,142,723

Computers — 0.48%
Dell International LLC/EMC Corp.
3.38	%,	12/15/2041 ^(a)		662,000		556,407
4.90	%,	10/01/2026		1,107,000		1,161,127
8.35	%,	07/15/2046		192,000		280,587
					$	1,998,121

Diversified Financial Services — 7.49%
AerCap Ireland Capital DAC/AerCap Global Aviation Trust
2.45	%,	10/29/2026		1,079,000		998,024
3.00	%,	10/29/2028		3,027,000		2,791,461
3.15	%,	02/15/2024		4,703,000		4,627,178
3.40	%,	10/29/2033		1,898,000		1,701,163
3.85	%,	10/29/2041		1,043,790		915,343
Air Lease Corp.
2.88	%,	01/15/2026		1,119,000		1,080,029
Ally Financial, Inc.
5.75	%,	11/20/2025		1,288,000		1,354,465
8.00	%,	11/01/2031		3,331,000		4,178,168
Aviation Capital Group LLC
1.95	%,	01/30/2026 ^(a)		3,293,000		3,024,251
Avolon Holdings Funding Ltd.
2.75	%,	02/21/2028 ^(a)		926,000		823,475
4.25	%,	04/15/2026 ^(a)		2,877,000		2,837,167
4.38	%,	05/01/2026 ^(a)		1,194,000		1,177,887
5.50	%,	01/15/2026 ^(a)		901,000		929,883
Blackstone Holdings Finance Co. LLC
2.85	%,	08/05/2051 ^(a)		1,156,342		929,368
3.20	%,	01/30/2052 ^(a)		680,000		588,520
Brookfield Finance LLC
3.45	%,	04/15/2050		888,000		779,743
Brookfield Finance, Inc.
2.72	%,	04/15/2031		883,000		814,853
4.85	%,	03/29/2029		1,271,000		1,354,746
					$	30,905,724

Electric — 7.95%
American Electric Power Co., Inc.
1.00	%,	11/01/2025		1,689,000		1,563,081
2.03	%,	03/15/2024		389,000		382,263
Commonwealth Edison Co.
4.00	%,	03/01/2049		1,667,000		1,729,089
Dominion Energy, Inc.
4.25	%,	06/01/2028		488,000		504,013

See accompanying notes.


		Schedule of Investments
		Principal Investment Grade Corporate Active ETF
		March 31, 2022 (unaudited)

				Principal
BONDS (continued)				Amount		Value

Electric (continued)
DTE Energy Co.
3.40	%,	06/15/2029	$	1,332,000	$	1,303,187
Duke Energy Carolinas LLC
3.55	%,	03/15/2052		500,000		493,928
Duke Energy Florida LLC
3.80	%,	07/15/2028		236,000		240,979
Duke Energy Ohio, Inc.
4.30	%,	02/01/2049		777,000		819,677
Entergy Corp.
1.90	%,	06/15/2028		882,000		797,525
Evergy, Inc.
2.90	%,	09/15/2029		888,000		848,732
Georgia Power Co.
3.25	%,	03/15/2051		474,000		410,960
3.70	%,	01/30/2050		120,000		111,491
NextEra Energy Capital Holdings, Inc.
1.88	%,	01/15/2027		762,000		714,630
2.44	%,	01/15/2032		381,000		348,397
3.50	%,	04/01/2029		632,000		636,894
NRG Energy, Inc.
2.00	%,	12/02/2025 ^(a)		1,761,000		1,655,834
2.45	%,	12/02/2027 ^(a)		662,000		610,565
4.45	%,	06/15/2029 ^(a)		875,588		875,946
Pacific Gas & Electric Co.
1.70	%,	11/15/2023		2,058,000		2,006,021
1.75	%,	06/16/2022		1,010,000		1,008,853
2.95	%,	03/01/2026		2,275,000		2,161,779
3.50	%,	06/15/2025		1,215,000		1,185,519
4.50	%,	07/01/2040		2,005,391		1,825,778
Public Service Co. of Colorado
4.05	%,	09/15/2049		635,000		667,981
Southern California Edison Co.
3.45	%,	02/01/2052		387,000		347,698
4.88	%,	03/01/2049		1,063,000		1,129,410
Southern Co.
1.75	%,	03/15/2028		952,000		856,161
(3-month USD LIBOR + 3.63%),
4.46	%,	03/15/2057		2,294,000		2,283,475
Southern Power Co.
0.90	%,	01/15/2026		1,395,000		1,277,935
4.95	%,	12/15/2046		309,000		326,468
Tampa Electric Co.
3.63	%,	06/15/2050		401,000		386,683
Tri-State Generation and Transmission Association, Inc.
6.00	%,	06/15/2040 ^(a)		435,000		511,685
Tucson Electric Power Co.
4.85	%,	12/01/2048		443,000		497,925
Virginia Electric & Power Co.
3.80	%,	04/01/2028 ^(e)		1,239,000		1,268,236
WEC Energy Group, Inc.
1.38	%,	10/15/2027		1,135,000		1,020,935
					$	32,809,733

Entertainment — 2.42%
Magallanes, Inc.
3.76	%,	03/15/2027 ^(a)		2,250,000		2,245,904
5.05	%,	03/15/2042 ^(a)		2,850,000		2,907,086

See accompanying notes.


			Schedule of Investments
			Principal Investment Grade Corporate Active ETF
			March 31, 2022 (unaudited)

				Principal
BONDS (continued)				Amount		Value

Entertainment (continued)
Magallanes, Inc. (continued)
5.14	%,	03/15/2052	$	2,500,000	$	2,557,737
5.39	%,	03/15/2062		2,200,000		2,272,772
					$	9,983,499

Food — 2.61%
JBS Finance Luxembourg SARL
3.63	%,	01/15/2032 ^(a)		840,000		768,608
JBS USA LUX SA/JBS USA Food Co./JBS USA Finance, Inc.
3.00	%,	05/15/2032 ^(a)		6,000		5,400
3.75	%,	12/01/2031 ^(a)		1,094,000		1,015,489
4.38	%,	02/02/2052 ^(a)		2,746,000		2,388,700
Kraft Heinz Foods Co.
4.38	%,	06/01/2046		2,000,000		1,975,280
Mars, Inc.
2.38	%,	07/16/2040 ^(a)		609,000		509,221
Pilgrim's Pride Corp.
3.50	%,	03/01/2032 ^(a)		1,464,000		1,278,050
Sysco Corp.
3.15	%,	12/14/2051		930,736		793,767
6.60	%,	04/01/2050		1,524,000		2,048,271
					$	10,782,786

Gas — 1.31%
CenterPoint Energy Resources Corp.
1.75	%,	10/01/2030		2,038,000		1,786,624
NiSource, Inc.
0.95	%,	08/15/2025 ^(e)		1,687,000		1,550,319
Piedmont Natural Gas Co., Inc.
3.50	%,	06/01/2029		1,381,000		1,370,371
Southern California Gas Co.
2.55	%,	02/01/2030		759,000		716,577
					$	5,423,891

Healthcare — Products — 1.30%
Boston Scientific Corp.
2.65	%,	06/01/2030		4,002,000		3,755,140
Medtronic, Inc.
4.63	%,	03/15/2045		39,000		44,958
PerkinElmer, Inc.
1.90	%,	09/15/2028		918,000		829,495
2.25	%,	09/15/2031		847,000		748,630
					$	5,378,223

Healthcare — Services — 1.23%
Centene Corp.
2.45	%,	07/15/2028		1,635,000		1,493,900
3.38	%,	02/15/2030		326,000		306,745
HCA, Inc.
5.63	%,	09/01/2028		1,144,000		1,236,950
Roche Holdings, Inc.
1.93	%,	12/13/2028 ^(a)		1,209,000		1,124,047
UnitedHealth Group, Inc.
2.75	%,	05/15/2040		1,000,000		898,133
					$	5,059,775

See accompanying notes.


				Schedule of Investments
				Principal Investment Grade Corporate Active ETF
				March 31, 2022 (unaudited)

					Principal
BONDS (continued)					Amount		Value

Home Builders — 1.02%
Lennar Corp.
4.75	%,	05/30/2025	^(e)	$	3,217,000	$	3,331,564
Toll Brothers Finance Corp.
4.35	%,	02/15/2028			874,000		878,095
						$	4,209,659

Insurance — 5.67%
AIA Group Ltd.
3.20	%,	09/16/2040 ^(a)	^,(e)		1,310,000		1,163,026
American International Group, Inc.
4.50	%,	07/16/2044			785,000		847,082
Athene Global Funding
1.45	%,	01/08/2026	^(a)		1,436,000		1,328,671
2.50	%,	03/24/2028	^(a)		2,468,000		2,272,922
2.55	%,	11/19/2030	^(a)		1,351,000		1,198,719
Athene Holding Ltd.
3.45	%,	05/15/2052			782,000		660,295
4.13	%,	01/12/2028			573,000		577,452
Corebridge Financial, Inc.
4.40	%,	04/05/2052			1,255,000		1,254,787
Enstar Group Ltd.
3.10	%,	09/01/2031			3,021,000		2,701,956
Equitable Financial Life Global Funding
1.80	%,	03/08/2028	^(a)		963,000		866,141
Everest Reinsurance Holdings, Inc.
3.13	%,	10/15/2052			1,033,000		854,028
Markel Corp.
4.30	%,	11/01/2047			1,523,000		1,550,865
Marsh & McLennan Cos., Inc.
2.90	%,	12/15/2051			739,000		614,109
New York Life Insurance Co.
3.75	%,	05/15/2050	^(a)		1,352,000		1,310,570
Swiss Re Finance Luxembourg SA
(5-year Treasury Constant Maturity Rate + 3.58%),
5.00	%,	04/02/2049 ^(a)	^,(b)		1,000,000		1,035,000
XLIT Ltd.
4.45	%,	03/31/2025			3,235,000		3,324,770
5.50	%,	03/31/2045			1,547,000		1,827,515
						$	23,387,908

Internet — 1.59%
Amazon.com, Inc.
2.70	%,	06/03/2060	^(e)		12,000		9,910
3.10	%,	05/12/2051			698,000		655,067
eBay, Inc.
3.65	%,	05/10/2051			1,923,000		1,774,430
Expedia Group, Inc.
3.80	%,	02/15/2028			2,097,000		2,085,878
4.63	%,	08/01/2027			1,120,000		1,163,397
Netflix, Inc.
4.88	%,	04/15/2028			822,000		862,077
						$	6,550,759

Investment Companies — 0.89%
Blackstone Private Credit Fund
4.70	%,	03/24/2025			3,630,000		3,682,984

See accompanying notes.


				Schedule of Investments
				Principal Investment Grade Corporate Active ETF
				March 31, 2022 (unaudited)

					Principal
BONDS (continued)					Amount		Value

Iron & Steel — 0.16%
Nucor Corp.
2.70	%,	06/01/2030		$	201,000	$	191,158
3.85	%,	04/01/2052			460,000		459,215
						$	650,373

Lodging — 0.21%
Hyatt Hotels Corp.
1.80	%,	10/01/2024			888,000		854,381

Media — 3.61%
Charter Communications Operating LLC/Charter Communications Operating
Capital
2.30	%,	02/01/2032			1,615,000		1,380,447
Comcast Corp.
2.89	%,	11/01/2051	^(a)		468,000		394,541
3.75	%,	04/01/2040			557,000		560,683
3.97	%,	11/01/2047			2,504,000		2,543,840
Fox Corp.
4.71	%,	01/25/2029			1,685,000		1,798,889
Paramount Global
2.90	%,	01/15/2027			4,187,000		4,083,467
5.25	%,	04/01/2044			728,000		763,901
Time Warner Cable LLC
5.50	%,	09/01/2041			1,688,000		1,752,283
5.88	%,	11/15/2040			1,491,000		1,602,392
						$	14,880,443

Mining — 0.85%
Newmont Corp.
2.25	%,	10/01/2030			2,051,000		1,874,471
Yamana Gold, Inc.
2.63	%,	08/15/2031			1,825,000		1,634,723
						$	3,509,194

Miscellaneous Manufacture — 0.72%
GE Capital International Funding Unlimited Co.
4.42	%,	11/15/2035			2,781,000		2,986,206

Oil & Gas — 1.95%
BP Capital Markets America, Inc.
3.00	%,	02/24/2050			653,000		564,023
3.59	%,	04/14/2027	^(e)		1,506,000		1,528,292
4.23	%,	11/06/2028			25,000		26,253
Canadian Natural Resources Ltd.
4.95	%,	06/01/2047			366,000		404,946
Devon Energy Corp.
4.50	%,	01/15/2030			1,452,000		1,498,369
Exxon Mobil Corp.
3.00	%,	08/16/2039			1,044,000		967,886
Marathon Oil Corp.
4.40	%,	07/15/2027			1,567,000		1,615,409
Shell International Finance BV
3.13	%,	11/07/2049			1,572,000		1,429,582
						$	8,034,760

See accompanying notes.


				Schedule of Investments
				Principal Investment Grade Corporate Active ETF
				March 31, 2022 (unaudited)

					Principal
BONDS (continued)					Amount		Value

Packaging & Containers — 0.20%
WRKCo, Inc.
3.00	%,	06/15/2033		$	889,000	$	830,279

Pharmaceuticals — 5.59%
AbbVie, Inc.
4.05	%,	11/21/2039			1,260,000		1,294,533
4.25	%,	11/21/2049			2,030,000		2,106,565
Bayer US Finance II LLC
4.38	%,	12/15/2028	^(a)		1,393,000		1,424,209
4.63	%,	06/25/2038	^(a)		1,292,000		1,340,356
Becton Dickinson and Co.
3.70	%,	06/06/2027			1,376,000		1,395,978
4.67	%,	06/06/2047			944,000		1,028,228
4.69	%,	12/15/2044			1,495,000		1,605,358
Bristol-Myers Squibb Co.
4.13	%,	06/15/2039			1,436,000		1,541,996
4.25	%,	10/26/2049			411,000		448,191
Cigna Corp.
4.38	%,	10/15/2028			2,668,000		2,806,525
CVS Health Corp.
4.78	%,	03/25/2038			1,173,000		1,281,899
5.05	%,	03/25/2048			4,337,000		4,911,613
Merck & Co., Inc.
2.75	%,	12/10/2051			528,000		459,909
Zoetis, Inc.
3.90	%,	08/20/2028	^(e)		1,400,000		1,437,028
						$	23,082,388

Pipelines — 2.83%
Eastern Gas Transmission & Storage, Inc.
3.00	%,	11/15/2029	^(a)		205,000		197,393
Enbridge, Inc.
2.50	%,	08/01/2033			1,496,000		1,328,261
Energy Transfer LP
3.75	%,	05/15/2030			2,861,000		2,814,533
5.15	%,	03/15/2045			1,480,000		1,493,584
6.25	%,	04/15/2049			356,000		408,502
Enterprise Products Operating LLC
4.20	%,	01/31/2050			1,735,000		1,721,594
Kinder Morgan, Inc.
3.60	%,	02/15/2051			943,000		837,268
MPLX LP
4.00	%,	03/15/2028			905,000		920,596
ONEOK, Inc.
4.45	%,	09/01/2049			543,000		521,087
Sabine Pass Liquefaction LLC
5.00	%,	03/15/2027			1,360,000		1,438,287
5.75	%,	05/15/2024			9,000		9,420
						$	11,690,525

Private Equity — 0.40%
KKR Group Finance Co. VIII LLC
3.50	%,	08/25/2050	^(a)		1,301,000		1,134,847
KKR Group Finance Co. X LLC
3.25	%,	12/15/2051	^(a)		624,000		520,060
						$	1,654,907

See accompanying notes.


				Schedule of Investments
				Principal Investment Grade Corporate Active ETF
				March 31, 2022 (unaudited)

					Principal
BONDS (continued)					Amount		Value

REITs — 2.78%
American Campus Communities Operating Partnership LP
2.25	%,	01/15/2029		$	1,556,000	$	1,421,976
Invitation Homes Operating Partnership LP
2.00	%,	08/15/2031			2,286,000		1,952,173
Kimco Realty Corp.
3.20	%,	04/01/2032			1,390,000		1,351,391
Realty Income Corp.
3.10	%,	12/15/2029			70		69
Simon Property Group LP
1.75	%,	02/01/2028			1,165,000		1,061,294
Spirit Realty LP
3.20	%,	01/15/2027			4,010,000		3,922,408
3.20	%,	02/15/2031			724,000		690,981
VICI Properties LP/VICI Note Co., Inc.
4.13	%,	08/15/2030	^(a)		1,088,000		1,050,312
						$	11,450,604

Retail — 0.14%
Home Depot, Inc.
3.30	%,	04/15/2040			582,000		560,546

Semiconductors — 2.06%
Broadcom, Inc.
4.11	%,	09/15/2028			507,000		513,022
Lam Research Corp.
4.88	%,	03/15/2049			299,000		356,164
Micron Technology, Inc.
3.37	%,	11/01/2041			2,046,000		1,827,774
4.19	%,	02/15/2027			2,043,000		2,096,476
NlVIDIA Corp.
3.50	%,	04/01/2040			1,982,000		1,996,446
3.50	%,	04/01/2050			932,000		941,889
QUALCOMM, Inc.
4.30	%,	05/20/2047			673,000		757,316
						$	8,489,087

Software — 2.97%
Fiserv, Inc.
4.40	%,	07/01/2049			1,606,000		1,658,271
Oracle Corp.
2.80	%,	04/01/2027			1,692,000		1,619,435
4.00	%,	07/15/2046			2,216,000		1,966,351
VMware, Inc.
1.80	%,	08/15/2028	^(e)		1,039,000		921,496
4.65	%,	05/15/2027			5,817,000		6,095,091
						$	12,260,644

Telecommunications — 4.60%
AT&T, Inc.
3.50	%,	06/01/2041			2,973,000		2,737,300
3.50	%,	09/15/2053			3,612,000		3,169,328
3.55	%,	09/15/2055			1,730,000		1,525,802
4.50	%,	03/09/2048			922,000		968,358
6.38	%,	03/01/2041			735,000		951,426

See accompanying notes.


	Schedule of Investments
	Principal Investment Grade Corporate Active ETF
	March 31, 2022 (unaudited)

			Principal
BONDS (continued)			Amount		Value

Telecommunications (continued)
T-Mobile USA, Inc.
	2.05%, 02/15/2028	$	1,642,000	$	1,499,661
Verizon Communications, Inc.
	2.36%, 03/15/2032 ^(a)		2,698,000		2,436,874
	2.65%, 11/20/2040		4,429,000		3,767,566
	3.88%, 03/01/2052		1,600,000		1,607,663
Vodafone Group PLC
	(5-year Treasury Constant Maturity Rate + 2.45%),
	3.25%, 06/04/2081 ^(b)		324,000		298,874
				$	18,962,852

Transportation — 1.18%
Burlington Northern Santa Fe LLC
	4.38%, 09/01/2042		391,000		421,677
FedEx Corp.
	4.10%, 02/01/2045		1,721,000		1,676,860
Union Pacific Corp.
	2.95%, 03/10/2052		1,103,000		976,254
	3.50%, 02/14/2053		1,840,000		1,800,371
				$	4,875,162

Trucking & Leasing — 0.20%
SMBC Aviation Capital Finance DAC
	1.90%, 10/15/2026 ^(a)		903,000		806,854

Water — 0.21%
Essential Utilities, Inc.
	2.40%, 05/01/2031		958,000		870,989
TOTAL BONDS				$	407,505,515
INVESTMENT COMPANIES — 0.46%			Shares Held		Value

Money Market Funds — 0.46%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(f),(g),(h),(i)}			266,735	$	266,735
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ⁽ⁱ⁾			1,650,531		1,650,531
TOTAL INVESTMENT COMPANIES				$	1,917,266
Total Investments				$	409,422,781
Other Assets and Liabilities — 0.78%					3,204,862
Total Net Assets — 100.00%				$	412,627,643


(a)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in
	transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these
	securities totaled $73,012,843 or 17.69% of net assets.
^(b)	Rate shown is as of period end. The rate may be a variable or floating rate or a fixed rate which may convert to a variable or
	floating rate in the future.
(c)	Perpetual security. Perpetual securities pay an indefinite stream of interest, but they may be called by the issuer at an earlier
	date. Date shown, if any, reflects the next call date or final legal maturity date. Rate shown is as of period end.
^(d)	Security is a contingent convertible security, ("CoCo"). CoCo's are hybrid debt securities that may convert to equity or have
	their principal written down upon occurrence of certain "triggers". At the end of the period, the value of these securities
	totaled $5,015,850 or 1.22% of net assets.
(e)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $262,118 or
	0.06% of net assets.
(f)	Non-income producing security.
^(g)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of
	these securities totaled $266,735 or 0.06% of net assets.

See accompanying notes.


				Schedule of Investments
			Principal Investment Grade Corporate Active ETF
				March 31, 2022 (unaudited)

^(h)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate
	as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
(i)	Current yield shown is as of period end.

	Portfolio Summary (unaudited)
Sector						Percent
Financial						35.86		%
Consumer, Non-cyclical						16.48		%
Communications							9.97	%
Utilities							9.48	%
Consumer, Cyclical							9.41	%
Industrial							5.97	%
Technology							5.51	%
Energy							4.78	%
Basic Materials							1.30	%
Money Market Funds							0.46	%
Other Assets and Liabilities							0.78	%
TOTAL NET ASSETS						100.00		%

				June 30, 2021		Purchases				Sales			March 31, 2022
Affiliated Securities				Value		Cost				Proceeds			Value
Principal Government Money
Market Fund — Institutional Class
0.00		%	$	2,138,163	$	32,814,010			$	34,685,438		$	266,735
			$	2,138,163	$	32,814,010			$	34,685,438		$	266,735

										Realized Gain
						Realized				from			Change in
						Gain/(Loss) on				Capital Gain			Unrealized
				Income ^(a)		Investments				Distributions			Gain/(Loss)
Principal Government Money
Market Fund — Institutional Class
0.00		%	$	—	$		—		$		—	$	—
			$	—	$		—		$		—	$	—

(a)	Amount excludes earnings from securities lending collateral.

Futures Contracts

												Value and Unrealized
Description and Expiration Date				Type	Contracts		Notional Amount				Appreciation/(Depreciation)
U.S. 5 Year Notes; June 2022				Short		141	$		16,170,938		$		381,089
U.S. 10 Year Notes; June 2022				Short		41			5,037,875				125,478
U.S. Treasury Ultra Bond; June 2022				Long		16			2,834,000				3,119
U.S. Long Bond CBT; June 2022				Long		22			3,301,375				(137,978	)
Total											$		371,708

See accompanying notes.


	Schedule of Investments
	Principal Millennials ETF
	March 31, 2022 (unaudited)

COMMON STOCKS — 99.57%		Shares Held		Value

Apparel — 2.85%
Carter's, Inc.		688	$	63,289
Columbia Sportswear Co.		559		50,606
Deckers Outdoor Corp. ^(a)		178		48,731
Fila Holdings Corp.		2,396		62,171
Hanesbrands, Inc.		3,109		46,293
SMCP SA ^(a),(b)		12,650		96,629
Urban Outfitters, Inc. ^(a)		13,318		334,415
Yue Yuen Industrial Holdings Ltd. ^(a)		37,500		60,511
			$	762,645

Beverages — 1.69%
Brown-Forman Corp., Class B		1,798		120,502
Constellation Brands, Inc., Class A		536		123,452
Monster Beverage Corp. ^(a)		1,343		107,306
Treasury Wine Estates Ltd.		11,589		100,422
			$	451,682

Building Materials — 0.86%
Fortune Brands Home & Security, Inc.		638		47,391
Masco Corp.		2,042		104,142
Mohawk Industries, Inc. ^(a)		636		78,991
			$	230,524

Commercial Services — 3.38%
Adyen NV ^(a),(b)		294		588,354
China Yuhua Education Corp. Ltd. ^(b)		122,000		27,723
Global Payments, Inc.		607		83,062
GMO Payment Gateway, Inc.		700		72,334
GXO Logistics, Inc. ^(a)		496		35,385
PayPal Holdings, Inc. ^(a)		487		56,322
PROG Holdings, Inc. ^(a)		1,412		40,623
			$	903,803

Computers — 0.65%
Apple, Inc.		1,001		174,785

Diversified Financial Services — 4.02%
Discover Financial Services		6,980		769,126
LexinFintech Holdings Ltd., ADR ^(a)		48,961		128,278
Rocket Cos., Inc., Class A		2,851		31,703
XP, Inc., Class A ^(a)		4,843		145,774
			$	1,074,881

Electronics — 0.61%
Garmin Ltd.		1,384		164,156

Engineering & Construction — 0.23%
HomeServe PLC		5,505		60,963

Entertainment — 5.57%
CTS Eventim AG & Co. KGaA ^(a)		8,516		584,279
DraftKings, Inc., Class A ^(a)		5,384		104,826
Universal Music Group NV		29,944		801,473
			$	1,490,578

Food — 4.61%
Albertsons Cos., Inc., Class A		3,206		106,600
Kroger Co.		18,355		1,053,026

See accompanying notes.


	Schedule of Investments
	Principal Millennials ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value

Food (continued)
Sprouts Farmers Market, Inc. ^(a)		2,297	$	73,458
			$	1,233,084

Home Builders — 0.57%
DR Horton, Inc.		1,372		102,228
Toll Brothers, Inc.		1,078		50,687
			$	152,915

Home Furnishings — 4.49%
Sleep Number Corp. ^(a)		3,424		173,631
Sony Group Corp.		9,400		982,931
Tempur Sealy International, Inc.		1,673		46,710
			$	1,203,272

Internet — 28.98%
AfreecaTV Co. Ltd.		10,660		1,301,662
Alibaba Group Holding Ltd., ADR ^(a)		789		85,843
Alphabet, Inc., Class C ^(a)		320		893,757
Amazon.com, Inc. ^(a)		39		127,138
ASOS PLC ^(a)		1,195		25,282
Baidu, Inc., ADR ^(a)		839		111,000
eBay, Inc.		1,997		114,348
Expedia Group, Inc. ^(a)		1,911		373,925
Farfetch Ltd., Class A ^(a)		9,290		140,465
Hello Group, Inc.		50,124		289,717
IAC/InterActiveCorp ^(a)		1,512		151,623
JD.com, Inc., Class A ^(a)		357		10,664
JOYY, Inc., ADR		7,882		289,506
Kakao Corp.		2,076		182,413
Kogan.com Ltd. ^(a),(c)		9,982		42,502
Meta Platforms, Inc., Class A ^(a)		2,253		500,977
Naspers Ltd., Class N		2,732		311,129
NCSoft Corp.		233		89,870
Netflix, Inc. ^(a)		234		87,654
Overstock.com, Inc. ^(a)		923		40,617
Pinduoduo, Inc., ADR ^(a)		4,904		196,699
Pinterest, Inc., Class A ^(a)		5,947		146,356
Rakuten Group, Inc.		15,200		120,736
RealReal, Inc. ^(a)		2,702		19,617
Revolve Group, Inc. ^(a)		11,073		594,509
Roku, Inc. ^(a)		1,339		167,737
Shutterstock, Inc.		668		62,177
Snap, Inc., Class A ^(a)		8,420		303,036
Temple & Webster Group Ltd. ^(a),(c)		13,182		65,991
Tencent Holdings Ltd.		2,400		114,649
Tencent Music Entertainment Group, ADR ^(a)		36,058		175,602
Trip.com Group Ltd., ADR ^(a)		12,429		287,359
Vimeo, Inc. ^(a)		2,478		29,439
Wayfair, Inc., Class A ^(a),(c)		1,574		174,368
Weibo Corp. ^(a)		1,808		44,314
ZOZO, Inc.		3,100		83,650
			$	7,756,331

Leisure Time — 1.43%
Camping World Holdings, Inc., Class A		13,693		382,719

Media — 5.90%
Comcast Corp., Class A		2,260		105,813

See accompanying notes.


	Schedule of Investments
	Principal Millennials ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value

Media (continued)
Fox Corp., Class B		1,704	$	61,821
Paramount Global, Class B		14,646		553,765
Sirius XM Holdings, Inc.		20,841		137,967
Vivendi SE		29,935		392,089
Walt Disney Co. ^(a)		2,386		327,264
			$	1,578,719

Real Estate — 0.64%
REA Group Ltd.		1,695		171,826

REITs — 4.61%
American Homes 4 Rent, Class A		1,787		71,534
AvalonBay Communities, Inc.		663		164,669
Duke Realty Corp.		2,917		169,361
EastGroup Properties, Inc.		417		84,768
Essex Property Trust, Inc.		450		155,466
Invitation Homes, Inc.		3,823		153,608
Prologis, Inc.		1,154		186,348
Segro PLC		14,102		249,255
			$	1,235,009

Retail — 16.01%
Academy Sports & Outdoors, Inc.		2,266		89,280
Bath & Body Works, Inc.		1,977		94,501
Bed Bath & Beyond, Inc. ^(a)		11,327		255,197
Dick's Sporting Goods, Inc.		837		83,717
Domino's Pizza, Inc.		333		135,534
Foot Locker, Inc.		1,087		32,240
Hennes & Mauritz AB, Class B		29,102		390,548
Hibbett, Inc.		888		39,374
Home Depot, Inc.		2,164		647,750
Industria de Diseno Textil SA		20,119		440,236
JD Sports Fashion PLC		40,086		78,067
Kingfisher PLC		20,770		69,685
Li Ning Co. Ltd.		28,271		243,974
Lowe's Cos., Inc.		643		130,008
Lululemon Athletica, Inc. ^(a)		399		145,727
Mr Price Group Ltd.		7,066		104,695
Pandora A/S		841		80,997
Pets at Home Group PLC		16,007		75,994
Qurate Retail, Inc., Series A		5,947		28,308
Signet Jewelers Ltd.		8,497		617,732
Truworths International Ltd.		28,565		114,065
Victoria's Secret & Co. ^(a)		659		33,846
Williams-Sonoma, Inc.		682		98,890
Zalando SE ^(a),(b)		5,011		254,997
			$	4,285,362

Semiconductors — 0.54%
Samsung Electronics Co. Ltd.		2,533		145,453

Software — 5.89%
Activision Blizzard, Inc.		7,103		569,021
Bilibili, Inc., ADR ^(a),(c)		6,134		156,908
Electronic Arts, Inc.		889		112,467
Fiserv, Inc. ^(a)		1,027		104,138
Microsoft Corp.		519		160,013
NetEase, Inc., ADR		1,750		156,958
Netmarble Corp. ^(b)		801		73,686

See accompanying notes.


		Schedule of Investments
		Principal Millennials ETF
		March 31, 2022 (unaudited)

COMMON STOCKS (continued)				Shares Held		Value

Software (continued)
Pearl Abyss Corp. ^(a)				1,676	$	137,587
Take-Two Interactive Software, Inc. ^(a)				692		106,388
					$	1,577,166

Telecommunications — 1.93%
AT&T, Inc.				21,822		515,654

Toys, Games & Hobbies — 2.19%
Funko, Inc., Class A ^(a)				25,167		434,131
Nintendo Co. Ltd.				300		151,971
					$	586,102

Transportation — 1.92%
Deutsche Post AG				3,322		160,044
FedEx Corp.				431		99,729
United Parcel Service, Inc., Class B				719		154,197
XPO Logistics, Inc. ^(a)				496		36,109
Yamato Holdings Co. Ltd.				3,400		64,040
					$	514,119
TOTAL COMMON STOCKS					$	26,651,748
INVESTMENT COMPANIES — 1.21%				Shares Held		Value

Money Market Funds — 1.21%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(a),(d),(e),(f)}				235,477	$	235,477
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(f)				88,823		88,823
TOTAL INVESTMENT COMPANIES					$	324,300
Total Investments					$	26,976,048
Other Assets and Liabilities — (0.78)%						(208,748	)

Total Net Assets — 100.00%					$	26,767,300

^(a)	Non-income producing security.
^(b)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in
	transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these
	securities totaled $1,041,389 or 3.89% of net assets.
^(c)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $213,402 or
	0.80% of net assets.
^(d)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate
	as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(e)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of
	these securities totaled $235,477 or 0.88% of net assets.
^(f)	Current yield shown is as of period end.

	Portfolio Summary (unaudited)
Sector		Percent
Communications		36.80	%
Consumer, Cyclical		33.12	%
Consumer, Non-cyclical		9.67	%
Financial		9.27	%
Technology		7.09	%
Industrial		3.62	%
Money Market Funds		1.21	%
Other Assets and Liabilities		(0.78	)%
TOTAL NET ASSETS		100.00	%

See accompanying notes.


			Schedule of Investments
			Principal Millennials ETF
			March 31, 2022 (unaudited)

			June 30, 2021		Purchases		Sales		March 31, 2022
Affiliated Securities			Value		Cost		Proceeds		Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	4,595,808	$	37,698,849	$	42,059,180	$	235,477
		$	4,595,808	$	37,698,849	$	42,059,180	$	235,477

							Realized Gain
					Realized		from		Change in
					Gain/(Loss) on		Capital Gain		Unrealized
			Income ^(a)		Investments		Distributions		Gain/(Loss)
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$	— $		—	$	—
		$	—	$	— $		—	$	—

^(a)Amount excludes earnings from securities lending collateral.

See accompanying notes.


	Schedule of Investments
	Principal Quality ETF
	March 31, 2022 (unaudited)

COMMON STOCKS — 99.77%		Shares Held		Value
Advertising — 0.65%
Interpublic Group of Cos., Inc.		15,835	$	561,351
Aerospace & Defense — 0.98%
Lockheed Martin Corp.		577		254,688
Northrop Grumman Corp.		1,319		589,883
			$	844,571

Agriculture — 1.40%
Archer-Daniels-Midland Co.		10,712		966,865
Philip Morris International, Inc.		2,472		232,220
			$	1,199,085

Apparel — 0.96%
NIKE, Inc., Class B		6,158		828,620
Banks — 0.26%
Truist Financial Corp.		4,012		227,480
Beverages — 1.83%
Brown-Forman Corp., Class B		3,830		256,687
Coca-Cola Co.		9,364		580,568
Keurig Dr Pepper, Inc.		6,462		244,910
Monster Beverage Corp. ^(a)		2,961		236,584
PepsiCo, Inc.		1,525		255,254
			$	1,574,003

Biotechnology — 2.54%
Incyte Corp. ^(a)		3,657		290,439
Moderna, Inc. ^(a)		5,471		942,435
Regeneron Pharmaceuticals, Inc. ^(a)		1,360		949,851
			$	2,182,725

Building Materials — 0.59%
Builders FirstSource, Inc. ^(a)		7,830		505,348
Chemicals — 1.09%
CF Industries Holdings, Inc.		3,076		317,013
LyondellBasell Industries NV, Class A		5,992		616,097
			$	933,110

Commercial Services — 6.94%
Automatic Data Processing, Inc.		2,848		648,034
Cintas Corp.		666		283,310
Gartner, Inc. ^(a)		2,996		891,190
Moody's Corp.		2,587		872,880
Robert Half International, Inc.		6,990		798,118
Rollins, Inc.		17,859		625,958
S&P Global, Inc.		1,551		636,189
Service Corp. International		13,812		909,106
Verisk Analytics, Inc.		1,410		302,628
			$	5,967,413

Computers — 2.36%
Accenture PLC, Class A		2,634		888,264
Apple, Inc.		5,045		880,907
Cognizant Technology Solutions Corp., Class A		2,898		259,864
			$	2,029,035

See accompanying notes.


Schedule of Investments
Principal Quality ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Distribution/Wholesale — 3.12%
Copart, Inc. ^(a)	4,742	$	594,979
Fastenal Co.	11,326		672,765
LKQ Corp.	5,322		241,672
Pool Corp.	1,272		537,865
WW Grainger, Inc.	1,222		630,295
		$	2,677,576

Diversified Financial Services — 8.22%
American Express Co.	1,284		240,108
BlackRock, Inc.	1,129		862,748
Blackstone, Inc.	6,531		829,045
Discover Financial Services	4,719		519,987
Intercontinental Exchange, Inc.	6,560		866,707
KKR & Co., Inc.	4,153		242,826
Mastercard, Inc., Class A	2,331		833,053
Nasdaq, Inc.	3,405		606,771
Raymond James Financial, Inc.	5,312		583,842
T Rowe Price Group, Inc.	5,815		879,170
Visa, Inc., Class A	2,694		597,448
		$	7,061,705

Electric — 1.39%
Duke Energy Corp.	2,487		277,698
Evergy, Inc.	13,468		920,403
		$	1,198,101

Electrical Components & Equipment — 1.00%
AMETEK, Inc.	4,491		598,112
Emerson Electric Co.	2,686		263,362
		$	861,474

Electronics — 3.99%
Agilent Technologies, Inc.	4,470		591,515
Allegion PLC	2,181		239,430
Amphenol Corp., Class A	7,667		577,709
Garmin Ltd.	5,275		625,668
Keysight Technologies, Inc. ^(a)	3,702		584,805
Mettler-Toledo International, Inc. ^(a)	591		811,555
		$	3,430,682

Environmental Control — 0.32%
Republic Services, Inc.	2,076		275,070

Food — 1.69%
Hershey Co.	4,119		892,299
Tyson Foods, Inc., Class A	6,288		563,593
		$	1,455,892

Healthcare — Products — 6.31%
Abbott Laboratories	6,969		824,851
Bruker Corp.	3,548		228,136
Cooper Cos., Inc.	1,423		594,231
Danaher Corp.	3,034		889,963
Edwards Lifesciences Corp. ^(a)	7,480		880,546
Hologic, Inc. ^(a)	3,511		269,715
IDEXX Laboratories, Inc. ^(a)	1,580		864,355
Intuitive Surgical, Inc. ^(a)	2,006		605,170

See accompanying notes.


	Schedule of Investments
	Principal Quality ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value
Healthcare — Products (continued)
Medtronic PLC		2,377	$	263,728
			$	5,420,695

Healthcare — Services — 3.72%
Anthem, Inc.		1,861		914,161
Charles River Laboratories International, Inc. ^(a)		859		243,930
IQVIA Holdings, Inc. ^(a)		3,652		844,379
Laboratory Corp. of America Holdings ^(a)		2,149		566,605
UnitedHealth Group, Inc.		1,227		625,733
			$	3,194,808

Household Products — 2.80%
Colgate-Palmolive Co.		10,819		820,405
Estee Lauder Cos., Inc., Class A		2,838		772,844
Procter & Gamble Co.		5,341		816,105
			$	2,409,354

Household Products/Wares — 0.69%
Church & Dwight Co., Inc.		5,957		592,007
Insurance — 6.94%
Aflac, Inc.		4,089		263,291
Aon PLC		857		279,065
Arch Capital Group Ltd. ^(a)		5,300		256,626
Berkshire Hathaway, Inc., Class B ^(a)		775		273,505
Brown & Brown, Inc.		12,434		898,605
Chubb Ltd.		4,129		883,193
Cincinnati Financial Corp.		6,845		930,646
Fidelity National Financial, Inc.		5,242		256,019
Markel Corp. ^(a)		677		998,738
Marsh & McLennan Cos., Inc.		5,409		921,802
			$	5,961,490

Internet — 1.31%
Alphabet, Inc., Class A ^(a)		311		865,000
CDW Corp.		1,447		258,854
			$	1,123,854

Iron & Steel — 1.57%
Nucor Corp.		4,428		658,222
Steel Dynamics, Inc.		8,255		688,715
			$	1,346,937

Machinery — Diversified — 2.64%
Dover Corp.		5,358		840,670
IDEX Corp.		3,037		582,284
Nordson Corp.		3,711		842,694
			$	2,265,648

Media — 1.04%
FactSet Research Systems, Inc.		2,053		891,310
Miscellaneous Manufacture — 1.92%
3M Co.		3,922		583,907
Illinois Tool Works, Inc.		3,887		813,938
Trane Technologies PLC		1,623		247,832
			$	1,645,677

See accompanying notes.


	Schedule of Investments
	Principal Quality ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value

Packaging & Containers — 0.72%
Packaging Corp. of America		3,956	$	617,571

Pharmaceuticals — 3.86%
AbbVie, Inc.		5,688		922,082
CVS Health Corp.		5,620		568,800
Johnson & Johnson		3,543		627,926
Merck & Co., Inc.		3,261		267,565
Pfizer, Inc.		17,898		926,579
			$	3,312,952

Private Equity — 1.02%
Carlyle Group, Inc.		17,935		877,201

Real Estate — 0.28%
CBRE Group, Inc., Class A ^(a)		2,579		236,030

REITs — 5.04%
American Tower Corp.		1,103		277,096
Crown Castle International Corp.		1,502		277,269
Digital Realty Trust, Inc.		1,850		262,330
Duke Realty Corp.		10,995		638,370
Equity LifeStyle Properties, Inc.		3,347		255,979
Extra Space Storage, Inc.		4,469		918,826
Mid-America Apartment Communities, Inc.		1,221		255,738
Public Storage		2,368		924,183
SBA Communications Corp.		823		283,194
Sun Communities, Inc.		1,379		241,725
			$	4,334,710

Retail — 7.47%
AutoZone, Inc. ^(a)		312		637,909
Chipotle Mexican Grill, Inc. ^(a)		381		602,753
Costco Wholesale Corp.		483		278,136
Home Depot, Inc.		2,662		796,816
Lowe's Cos., Inc.		2,638		533,377
McDonald's Corp.		2,379		588,279
O'Reilly Automotive, Inc. ^(a)		1,285		880,174
Starbucks Corp.		6,348		577,478
Target Corp.		2,920		619,682
Tractor Supply Co.		1,227		286,345
Ulta Beauty, Inc. ^(a)		1,553		618,436
			$	6,419,385

Semiconductors — 2.90%
Applied Materials, Inc.		1,859		245,016
KLA Corp.		1,671		611,686
Lam Research Corp.		442		237,624
Microchip Technology, Inc.		3,550		266,747
NVIDIA Corp.		1,022		278,863
QUALCOMM, Inc.		1,451		221,742
Texas Instruments, Inc.		3,426		628,602
			$	2,490,280

Software — 6.10%
Adobe, Inc. ^(a)		534		243,301
Broadridge Financial Solutions, Inc.		1,708		265,952
Fair Isaac Corp. ^(a)		1,236		576,544
Jack Henry & Associates, Inc.		4,755		936,973
Microsoft Corp.		2,787		859,260

See accompanying notes.


		Schedule of Investments
		Principal Quality ETF
		March 31, 2022 (unaudited)

COMMON STOCKS (continued)				Shares Held		Value

Software (continued)
Oracle Corp.				3,290	$	272,182
Paychex, Inc.				7,059		963,342
SS&C Technologies Holdings, Inc.				7,771		582,980
Veeva Systems, Inc., Class A ^(a)				2,545		540,711
					$	5,241,245

Transportation — 3.37%
Expeditors International of Washington, Inc.				8,131		838,794
Old Dominion Freight Line, Inc.				1,855		554,051
Union Pacific Corp.				2,369		647,235
United Parcel Service, Inc., Class B				3,994		856,553
					$	2,896,633

Water — 0.74%
American Water Works Co., Inc.				3,856		638,284
TOTAL COMMON STOCKS					$	85,729,312
INVESTMENT COMPANIES — 0.20%				Shares Held		Value

Money Market Fund — 0.20%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(b)				176,068	$	176,068
TOTAL INVESTMENT COMPANIES					$	176,068
Total Investments					$	85,905,380
Other Assets and Liabilities — 0.03%						24,217
Total Net Assets — 100.00%					$	85,929,597

^(a)	Non-income producing security.
^(b)	Current yield shown is as of period end.

	Portfolio Summary (unaudited)
Sector		Percent
Consumer, Non-cyclical		32.75	%
Financial		20.51	%
Industrial		15.81	%
Consumer, Cyclical		11.55	%
Technology		11.36	%
Communications		3.00	%
Basic Materials		2.65	%
Utilities		2.14	%
Money Market Fund		0.20	%
Other Assets and Liabilities		0.03	%
TOTAL NET ASSETS		100.00	%

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
March 31, 2022 (unaudited)

		Principal
BONDS — 96.84%		Amount		Value

Banks — 39.40%
Bank of America Corp.
(5-year Treasury Constant Maturity Rate + 2.76%),
4.38%, 01/27/2027 ^(a),(b)	$	4,714,000	$	4,430,217
(3-month USD LIBOR + 4.55%),
6.30%, 03/10/2026 ^(a),(b)		766,000		814,603
Bank of Montreal
(5-year Treasury Constant Maturity Rate + 2.98%),
4.80%, 08/25/2024 ^(a),(b),(c)		3,546,000		3,516,568
Bank of New York Mellon Corp.
(5-year Treasury Constant Maturity Rate + 3.35%),
3.70%, 03/20/2026 ^(a),(b)		15,141,000		14,383,950
(5-year Treasury Constant Maturity Rate + 2.63%),
3.75%, 12/20/2026 ^(a),(b)		2,908,000		2,688,155
(5-year Treasury Constant Maturity Rate + 4.36%),
4.70%, 09/20/2025 ^(a),(b)		734,000		751,616
Bank of Nova Scotia
(5-year Treasury Constant Maturity Rate + 4.55%),
4.90%, 06/04/2025 ^(a),(b)		4,915,000		4,915,000
Citigroup, Inc.
(5-year Treasury Constant Maturity Rate + 3.42%),
3.88%, 02/18/2026 ^(a),(b)		6,905,000		6,507,962
(5-year Treasury Constant Maturity Rate + 3.60%),
4.00%, 12/10/2025 ^(a),(b)		9,288,000		8,916,480
(3-month USD LIBOR + 3.91%),
5.95%, 05/15/2025 ^(a),(b)		2,439,000		2,486,073
Citizens Financial Group, Inc.
(5-year Treasury Constant Maturity Rate + 3.22%),
4.00%, 10/06/2026 ^(a),(b)		2,343,000		2,149,702
(5-year Treasury Constant Maturity Rate + 5.31%),
5.65%, 10/06/2025 ^(a),(b)		3,081,000		3,204,394
(3-month USD LIBOR + 3.16%),
6.38%, 04/06/2024 ^(a),(b)		2,826,000		2,762,415
Comerica, Inc.
(5-year Treasury Constant Maturity Rate + 5.29%),
5.63%, 07/01/2025 ^(a),(b)		625,000		648,438
Fifth Third Bancorp
(5-year Treasury Constant Maturity Rate + 4.22%),
4.50%, 09/30/2025 ^(a),(b)		1,014,000		996,255
Goldman Sachs Group, Inc.
(5-year Treasury Constant Maturity Rate + 2.92%),
3.65%, 08/10/2026 ^(a),(b)		1,965,000		1,797,975
(5-year Treasury Constant Maturity Rate + 2.97%),
3.80%, 05/10/2026 ^(a),(b)		1,540,000		1,427,388
(5-year Treasury Constant Maturity Rate + 2.95%),
4.13%, 11/10/2026 ^(a),(b)		5,192,000		4,868,798
(5-year Treasury Constant Maturity Rate + 3.62%),
5.50%, 08/10/2024 ^(a),(b),(c)		5,772,000		5,889,172
HSBC Capital Funding Dollar 1 LP
(3-month USD LIBOR + 4.98%),
10.18%, 06/30/2030 ^(a),(b)		5,586,000		8,546,580
Huntington Bancshares, Inc.
(7-year Treasury Constant Maturity Rate + 4.05%),
4.45%, 10/15/2027 ^(a),(b),(c)		2,141,000		2,119,590
(10-year Treasury Constant Maturity Rate + 4.95%),
5.63%, 07/15/2030 ^(a),(b)		6,928,000		7,215,512

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Banks (continued)
JPMorgan Chase & Co.
(5-year Treasury Constant Maturity Rate + 2.85%),
3.65%, 06/01/2026 ^(a),(b)	$	7,886,000	$	7,373,410
(3-month USD LIBOR + 3.30%),
6.00%, 08/01/2023 ^(a),(b)		4,252,000		4,305,150
(3-month USD LIBOR + 3.78%),
6.75%, 02/01/2024 ^(a),(b)		5,002,000		5,219,887
M&T Bank Corp.
(5-year Treasury Constant Maturity Rate + 2.68%),
3.50%, 09/01/2026 ^(a),(b)		3,938,000		3,539,199
PNC Financial Services Group, Inc.
(5-year Treasury Constant Maturity Rate + 2.60%),
3.40%, 09/15/2026 ^(a),(b)		2,564,000		2,308,882
SVB Financial Group
(5-year Treasury Constant Maturity Rate + 3.20%),
4.00%, 05/15/2026 ^(a),(b)		2,586,000		2,392,050
(5-year Treasury Constant Maturity Rate + 3.07%),
4.25%, 11/15/2026 ^(a),(b)		4,963,000		4,590,775
Truist Financial Corp.
(5-year Treasury Constant Maturity Rate + 3.00%),
4.80%, 09/01/2024 ^(a),(b)		7,720,000		7,584,900
(5-year Treasury Constant Maturity Rate + 4.61%),
4.95%, 09/01/2025 ^(a),(b)		1,726,000		1,767,424
U.S. Bancorp
(5-year Treasury Constant Maturity Rate + 2.54%),
3.70%, 01/15/2027 ^(a),(b)		10,250,000		9,276,250
Wells Fargo & Co.
(5-year Treasury Constant Maturity Rate + 3.45%),
3.90%, 03/15/2026 ^(a),(b)		12,125,000		11,622,419
(3-month USD LIBOR + 3.99%),
5.88%, 06/15/2025 ^(a),(b)		5,289,000		5,525,947
			$	156,543,136

Diversified Financial Services — 10.47%
Ally Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.87%),
4.70%, 05/15/2026 ^(a),(b)		5,087,000		4,788,444
(7-year Treasury Constant Maturity Rate + 3.48%),
4.70%, 05/15/2028 ^(a),(b)		587,000		534,170
American Express Co.
(5-year Treasury Constant Maturity Rate + 2.85%),
3.55%, 09/15/2026 ^(a),(b)		11,497,000		10,477,216
Capital One Financial Corp.
(5-year Treasury Constant Maturity Rate + 3.16%),
3.95%, 09/01/2026 ^(a),(b)		4,845,000		4,506,335
Charles Schwab Corp.
(5-year Treasury Constant Maturity Rate + 3.17%),
4.00%, 06/01/2026 ^(a),(b)		10,399,000		9,957,042
(5-year Treasury Constant Maturity Rate + 4.97%),
5.38%, 06/01/2025 ^(a),(b)		4,626,000		4,764,780
Discover Financial Services
(5-year Treasury Constant Maturity Rate + 5.78%),
6.13%, 06/23/2025 ^(a),(b),(c)		6,323,000		6,580,220
			$	41,608,207

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Electric — 12.09%
Algonquin Power & Utilities Corp.
(5-year Treasury Constant Maturity Rate + 3.25%),
4.75%, 01/18/2082 ^(b)	$	3,666,000	$	3,418,178
American Electric Power Co., Inc.
(5-year Treasury Constant Maturity Rate + 2.68%),
3.88%, 02/15/2062 ^(b)		3,484,000		3,218,664
CMS Energy Corp.
(5-year Treasury Constant Maturity Rate + 2.90%),
3.75%, 12/01/2050 ^(b)		3,055,000		2,696,038
(5-year Treasury Constant Maturity Rate + 4.12%),
4.75%, 06/01/2050 ^(b)		2,971,000		2,941,290
Dominion Energy, Inc.
(5-year Treasury Constant Maturity Rate + 2.99%),
4.65%, 12/15/2024 ^(a),(b)		13,749,000		13,611,510
Duke Energy Corp.
(5-year Treasury Constant Maturity Rate + 2.32%),
3.25%, 01/15/2082 ^(b)		3,132,000		2,776,089
(5-year Treasury Constant Maturity Rate + 3.39%),
4.88%, 09/16/2024 ^(a),(b)		9,356,000		9,455,454
Emera, Inc.
(3-month USD LIBOR + 5.44%),
6.75%, 06/15/2076 ^(b)		6,939,000		7,303,298
Southern Co.
(5-year Treasury Constant Maturity Rate + 3.73%),
4.00%, 01/15/2051 ^(b)		2,710,000		2,621,925
			$	48,042,446

Gas — 1.50%
NiSource, Inc.
(5-year Treasury Constant Maturity Rate + 2.84%),
5.65%, 06/15/2023 ^(a),(b)		6,070,000		5,948,600

Hand/Machine Tools — 0.96%
Stanley Black & Decker, Inc.
(5-year Treasury Constant Maturity Rate + 2.66%),
4.00%, 03/15/2060 ^(b)		3,861,000		3,821,348

Insurance — 23.35%
Allstate Corp.
(3-month USD LIBOR + 2.94%),
5.75%, 08/15/2053 ^(b)		3,861,000		3,841,695
American International Group, Inc.
(3-month USD LIBOR + 2.87%),
5.75%, 04/01/2048 ^(b)		1,602,000		1,611,131
Argentum Netherlands BV for Swiss Re Ltd.
(3-month USD LIBOR + 3.78%),
5.63%, 08/15/2052 ^(b)		5,600,000		5,779,984
Argentum Netherlands BV for Zurich Insurance Co. Ltd.
(5-year Treasury Constant Maturity Rate + 3.27%),
5.13%, 06/01/2048 ^(b)		4,000,000		4,120,080
AXA SA
(3-month USD LIBOR + 2.26%),
6.38%, 12/14/2036 ^(a),(b),(d)		5,119,000		6,534,045
Cloverie PLC for Zurich Insurance Co. Ltd.
(3-month USD LIBOR + 4.92%),
5.63%, 06/24/2046 ^(b)		5,600,000		5,866,896

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Insurance (continued)
Equitable Holdings, Inc.
(5-year Treasury Constant Maturity Rate + 4.74%),
4.95%, 09/15/2025 ^(a),(b)	$	3,961,000	$	3,891,683
Liberty Mutual Group, Inc.
(5-year Treasury Constant Maturity Rate + 3.32%),
4.13%, 12/15/2051 ^(b),(d)		3,107,000		2,928,348
Meiji Yasuda Life Insurance Co.
(5-year Swap rate + 4.23%),
5.20%, 10/20/2045 ^(b),(d)		3,861,000		4,020,768
MetLife, Inc.
(5-year Treasury Constant Maturity Rate + 3.58%),
3.85%, 09/15/2025 ^(a),(b),(c)		7,178,000		7,078,944
9.25%, 04/08/2068 ^(d)		5,629,000		7,309,812
Nippon Life Insurance Co.
(5-year Treasury Constant Maturity Rate + 2.65%),
2.75%, 01/21/2051 ^(b),(d)		5,067,000		4,547,632
(5-year Treasury Constant Maturity Rate + 2.60%),
2.90%, 09/16/2051 ^(b),(d)		2,888,000		2,614,411
Prudential Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.04%),
3.70%, 10/01/2050 ^(b)		10,121,000		9,274,884
(3-month USD LIBOR + 3.92%),
5.63%, 06/15/2043 ^(b)		6,036,000		6,073,725
Sumitomo Life Insurance Co.
(5-year Treasury Constant Maturity Rate + 2.75%),
3.38%, 04/15/2081 ^(b),(d)		4,672,000		4,490,726
(3-month USD LIBOR + 4.44%),
6.50%, 09/20/2073 ^(b),(d)		7,749,000		8,076,008
Voya Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.36%),
6.13%, 09/15/2023 ^(a),(b)		3,861,000		3,832,043
Zurich Finance Ireland Designated Activity Co.
(5-year Treasury Constant Maturity Rate + 2.78%),
3.00%, 04/19/2051 ^(b)		1,000,000		882,500
			$	92,775,315

Oil & Gas — 1.82%
BP Capital Markets PLC
(5-year Treasury Constant Maturity Rate + 4.04%),
4.38%, 06/22/2025 ^(a),(b)		5,312,000		5,341,216
(5-year Treasury Constant Maturity Rate + 4.40%),
4.88%, 03/22/2030 ^(a),(b)		1,898,000		1,902,745
			$	7,243,961

Pipelines — 5.12%
Enbridge, Inc.
(5-year Treasury Constant Maturity Rate + 5.31%),
5.75%, 07/15/2080 ^(b)		2,240,000		2,318,400
(3-month USD LIBOR + 3.89%),
6.00%, 01/15/2077 ^(b)		5,772,000		5,916,376
Enterprise Products Operating LLC
(3-month USD LIBOR + 3.03%),
5.25%, 08/16/2077 ^(b)		3,861,000		3,629,778

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value
Pipelines (continued)
Transcanada Trust
(6-month Secured Overnight Financing Rate + 4.42%),
5.50%, 09/15/2079 ^(b)	$	8,475,000	$	8,458,050
			$	20,322,604

REITs — 0.87%
Scentre Group Trust 2
(5-year Treasury Constant Maturity Rate + 4.38%),
4.75%, 09/24/2080 ^(b),(d)		1,079,000		1,058,769
(5-year Treasury Constant Maturity Rate + 4.69%),
5.13%, 09/24/2080 ^(b),(d)		2,426,000		2,380,512
			$	3,439,281

Telecommunications — 1.26%
Vodafone Group PLC
(5-year Swap rate + 4.87%),
7.00%, 04/04/2079 ^(b)		4,533,000		5,005,429
TOTAL BONDS			$	384,750,327


INVESTMENT COMPANIES — 1.52%		Shares Held		Value

Money Market Funds — 1.52%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(e),(f),(g),(h)}		1,116,810	$	1,116,810
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(h)		4,937,085		4,937,085
TOTAL INVESTMENT COMPANIES		$		6,053,895
Total Investments		$		390,804,222
Other Assets and Liabilities — 1.64%				6,496,954

Total Net Assets — 100.00%		$		397,301,176

^(a)	Perpetual security. Perpetual securities pay an indefinite stream of interest, but they may be called by the issuer at an earlier
	date. Date shown, if any, reflects the next call date or final legal maturity date. Rate shown is as of period end.
^(b)	Rate shown is as of period end. The rate may be a variable or floating rate or a fixed rate which may convert to a variable or
	floating rate in the future.
^(c)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $1,094,562 or
	0.28% of net assets.
^(d)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in
	transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these
	securities totaled $43,961,031 or 11.06% of net assets.
^(e)	Non-income producing security.
^(f)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of
	these securities totaled $1,116,810 or 0.28% of net assets.
^(g)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate
	as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(h)	Current yield shown is as of period end.

See accompanying notes.


			Schedule of Investments
		Principal Spectrum Preferred Securities Active ETF
			March 31, 2022 (unaudited)

Portfolio Summary (unaudited)
Sector				Percent
Financial					74.09	%
Utilities					13.59	%
Energy					6.94	%
Money Market Funds					1.52	%
Communications					1.26	%
Industrial					0.96	%
Other Assets and Liabilities					1.64	%
TOTAL NET ASSETS				100.00		%

			June 30, 2021	Purchases			Sales		March 31, 2022
Affiliated Securities			Value		Cost		Proceeds		Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	10,355,640	$	67,154,670	$	76,393,500	$	1,116,810
		$	10,355,640	$	67,154,670	$	76,393,500	$	1,116,810

							Realized Gain
					Realized		from		Change in
				Gain/(Loss) on			Capital Gain		Unrealized
			Income ^(a)	Investments			Distributions		Gain/(Loss)
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$	— $		—	$	—
		$	—	$	— $		—	$	—

^(a)Amount excludes earnings from securities lending collateral.

See accompanying notes.


Schedule of Investments
Principal Spectrum Tax-Advantaged Dividend Active ETF
March 31, 2022 (unaudited)

PREFERRED STOCKS — 11.46%	Shares Held		Value

Banks — 4.86%
Associated Banc-Corp.; Series F
5.63%, 09/15/2025 ^(a)	2,070	$	52,961
Bank of America Corp.; Series NN
4.38%, 11/03/2025 ^(a)	4,380		94,827
Fulton Financial Corp.; Series A
5.13%, 01/15/2026 ^(a)	9,200		205,344
Morgan Stanley; Series I
(3-month USD LIBOR + 3.71%),
6.38%, 10/15/2024 ^(a)	17,030		452,657
Synovus Financial Corp.; Series E
(5-year Treasury Constant Maturity Rate + 4.13%),
5.88%, 07/01/2024 ^(a)	11,500		301,300
		$	1,107,089

Insurance — 3.98%
Allstate Corp.; Series H
5.10%, 10/15/2024 ^(a)	11,500		285,660
American International Group, Inc.; Series A
5.85%, 03/15/2024 ^(a)	8,019		208,173
MetLife, Inc.; Series F
4.75%, 03/15/2025 ^(a)	17,250		411,240
		$	905,073

Telecommunications — 2.62%
AT&T, Inc.; Series A
5.00%, 12/12/2024 ^(a)	11,381		259,487
AT&T, Inc.; Series C
4.75%, 02/18/2025 ^(a)	15,395		336,843
		$	596,330
TOTAL PREFERRED STOCKS		$	2,608,492


		Principal
BONDS — 86.54%		Amount		Value

Banks — 70.65%
Bank of America Corp.
(3-month USD LIBOR + 3.90%),
6.10%, 03/17/2025 ^(a),(b)	$	230,000	$	239,903
(3-month USD LIBOR + 4.55%),
6.30%, 03/10/2026 ^(a),(b)		575,000		611,484
Bank of New York Mellon Corp.
(5-year Treasury Constant Maturity Rate + 3.35%),
3.70%, 03/20/2026 ^(a),(b)		230,000		218,500
(5-year Treasury Constant Maturity Rate + 4.36%),
4.70%, 09/20/2025 ^(a),(b)		575,000		588,800
Bank of Nova Scotia
(5-year Treasury Constant Maturity Rate + 4.55%),
4.90%, 06/04/2025 ^(a),(b)		575,000		575,000
Citigroup, Inc.
(5-year Treasury Constant Maturity Rate + 3.42%),
3.88%, 02/18/2026 ^(a),(b)		335,000		315,737
Citizens Financial Group, Inc.
(5-year Treasury Constant Maturity Rate + 5.31%),
5.65%, 10/06/2025 ^(a),(b)		575,000		598,029
Comerica, Inc.
(5-year Treasury Constant Maturity Rate + 5.29%),
5.63%, 07/01/2025 ^(a),(b)		575,000		596,562

See accompanying notes.


Schedule of Investments
Principal Spectrum Tax-Advantaged Dividend Active ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Banks (continued)
Credit Agricole SA
(5-year Swap rate + 4.90%),
7.88%, 01/23/2024 ^(a),(b),(c)	$	861,000	$	907,279
Credit Suisse Group AG
(5-year Treasury Constant Maturity Rate + 4.82%),
6.38%, 08/21/2026 ^{(a),(b),(c),(d)}		384,000		379,035
(5-year Swap rate + 5.11%),
7.13%, 07/29/2022 ^(a),(b),(c)		500,000		500,625
Fifth Third Bancorp
(5-year Treasury Constant Maturity Rate + 4.22%),
4.50%, 09/30/2025 ^(a),(b)		548,000		538,410
Goldman Sachs Group, Inc.
(5-year Treasury Constant Maturity Rate + 2.97%),
3.80%, 05/10/2026 ^(a),(b)		438,000		405,971
HSBC Holdings PLC
(5-year Swap rate + 4.37%),
6.38%, 03/30/2025 ^(a),(b),(c)		861,000		890,851
Huntington Bancshares, Inc.
(10-year Treasury Constant Maturity Rate + 4.95%),
5.63%, 07/15/2030 ^(a),(b)		575,000		598,863
ING Groep NV
(5-year Treasury Constant Maturity Rate + 4.34%),
5.75%, 11/16/2026 ^(a),(b),(c)		861,000		865,735
JPMorgan Chase & Co.
(5-year Treasury Constant Maturity Rate + 2.85%),
3.65%, 06/01/2026 ^(a),(b)		110,000		102,850
Lloyds Banking Group PLC
(5-year Swap rate + 4.50%),
7.50%, 09/27/2025 ^(a),(b),(c)		861,000		915,170
M&T Bank Corp.
(3-month USD LIBOR + 3.52%),
5.13%, 11/01/2026 ^(a),(b)		247,000		247,000
Natwest Group PLC
(5-year Swap rate + 5.72%),
8.00%, 08/10/2025 ^(a),(b),(c)		861,000		935,304
Nordea Bank Abp
(5-year Treasury Constant Maturity Rate + 4.11%),
6.63%, 03/26/2026 ^{(a),(b),(c),(d)}		861,000		899,487
Societe Generale SA
(5-year Swap rate + 4.98%),
7.88%, 12/18/2023 ^(a),(b),(c)		824,000		861,080
Standard Chartered PLC
(5-year Swap rate + 6.30%),
7.50%, 04/02/2022 ^(a),(b),(c)		824,000		824,000
SVB Financial Group
(5-year Treasury Constant Maturity Rate + 3.20%),
4.00%, 05/15/2026 ^(a),(b)		110,000		101,750
Truist Financial Corp.
(5-year Treasury Constant Maturity Rate + 4.61%),
4.95%, 09/01/2025 ^(a),(b)		575,000		588,800
U.S. Bancorp
(5-year Treasury Constant Maturity Rate + 2.54%),
3.70%, 01/15/2027 ^(a),(b)		209,000		189,145
UBS Group AG
(5-year Swap rate + 4.34%),
7.00%, 01/31/2024 ^(a),(b),(c)		861,000		898,290

See accompanying notes.


Schedule of Investments
Principal Spectrum Tax-Advantaged Dividend Active ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Banks (continued)
Wells Fargo & Co.
(5-year Treasury Constant Maturity Rate + 3.45%),
3.90%, 03/15/2026 ^(a),(b)	$	328,000	$	314,404
(3-month USD LIBOR + 3.99%),
5.88%, 06/15/2025 ^(a),(b)		355,000		370,904
			$	16,078,968

Diversified Financial Services — 8.38%
Ally Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.87%),
4.70%, 05/15/2026 ^(a),(b)		220,000		207,088
Capital One Financial Corp.
(5-year Treasury Constant Maturity Rate + 3.16%),
3.95%, 09/01/2026 ^(a),(b)		209,000		194,391
Charles Schwab Corp.
(5-year Treasury Constant Maturity Rate + 3.17%),
4.00%, 06/01/2026 ^(a),(b)		328,000		314,060
(5-year Treasury Constant Maturity Rate + 4.97%),
5.38%, 06/01/2025 ^(a),(b)		575,000		592,250
Discover Financial Services
(5-year Treasury Constant Maturity Rate + 5.78%),
6.13%, 06/23/2025 ^(a),(b)		575,000		598,391
			$	1,906,180

Electric — 4.55%
Dominion Energy, Inc.
(5-year Treasury Constant Maturity Rate + 2.99%),
4.65%, 12/15/2024 ^(a),(b)		460,000		455,400
Duke Energy Corp.
(5-year Treasury Constant Maturity Rate + 3.39%),
4.88%, 09/16/2024 ^(a),(b)		575,000		581,112
			$	1,036,512

Insurance — 2.96%
MetLife, Inc.
(5-year Treasury Constant Maturity Rate + 3.58%),
3.85%, 09/15/2025 ^(a),(b)		220,000		216,964
Voya Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.36%),
6.13%, 09/15/2023 ^(a),(b)		460,000		456,550
			$	673,514
TOTAL BONDS			$	19,695,174


INVESTMENT COMPANIES — 1.14%	Shares Held		Value
Money Market Fund — 1.14%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(e)	259,769	$	259,769
TOTAL INVESTMENT COMPANIES		$	259,769
Total Investments		$	22,563,435
Other Assets and Liabilities — 0.86%			195,534
Total Net Assets — 100.00%		$	22,758,969

See accompanying notes.

Schedule of Investments

Principal Spectrum Tax-Advantaged Dividend Active ETF

March 31, 2022 (unaudited)

^(a)	Perpetual security. Perpetual securities pay an indefinite stream of interest, but they may be called by the issuer at an earlier date. Date shown, if any, reflects the next call date or final legal maturity date. Rate shown is as of period end.
^(b)	Rate shown is as of period end. The rate may be a variable or floating rate or a fixed rate which may convert to a variable or floating rate in the future.
^(c)	Security is a contingent convertible security, ("CoCo"). CoCo's are hybrid debt securities that may convert to equity or have their principal written down upon occurrence of certain "triggers". At the end of the period, the value of these securities totaled $8,876,856 or 39.00% of net assets.
^(d)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these securities totaled $1,278,522 or 5.62% of net assets.
^(e)	Current yield shown is as of period end.


Portfolio Summary (unaudited)

Sector	Percent
Financial	90.83	%
Utilities	4.55	%
Communications	2.62	%
Money Market Fund	1.14	%
Other Assets and Liabilities	0.86	%
TOTAL NET ASSETS	100.00	%

See accompanying notes.


Schedule of Investments
Principal Ultra-Short Active Income ETF
March 31, 2022 (unaudited)

		Principal
BONDS — 96.96%		Amount		Value

Asset-Backed Securities — 19.97%
AmeriCredit Automobile Receivables Trust 2021-1
0.28%, 06/18/2024	$	59,409	$	59,297
CPS Auto Receivables Trust 2021-B
0.37%, 03/17/2025 ^(a)		34,511		34,373
CPS Auto Receivables Trust 2021-C
0.33%, 07/15/2024 ^(a)		91,162		90,866
CPS Auto Receivables Trust 2022-A
0.98%, 04/16/2029 ^(a)		137,335		136,261
GreatAmerica Leasing Receivables Funding LLC
0.27%, 06/15/2023 ^(a)		33,051		32,923
JFIN CLO 2017-II Ltd.
(3-month USD LIBOR +0.99%),
1.92%, 09/20/2029 ^(a)		250,000		248,461
Madison Park Funding Ltd.2015-18A
(3-month USD LIBOR + 0.94%),
1.20%, 10/21/2030 ^(a)		250,000		248,466
TCI-Flatiron CLO 2016-1 Ltd.
(3-month Term Secured Overnight Financing Rate +1.10%),
1.27%, 01/17/2032 ^(a)		250,000		249,141
Trafigura Securitisation Finance PLC
(1-month USD LIBOR + 0.53%),
0.93%, 01/15/2025 ^(a)		250,000		249,100
Westlake Automobile Receivables Trust 2020-2A
0.93%, 02/15/2024 ^(a)		20,720		20,714
Westlake Automobile Receivables Trust 2022-1
1.97%, 12/16/2024		200,000		199,583
World Omni Auto Receivables Trust 2021-A
0.17%, 02/15/2024		14,574		14,550
World Omni Select Auto Trust 2021-A
0.29%, 02/18/2025		114,015		113,246
			$	1,696,981

Banks — 27.40%
Bank of Montreal
0.95%, 03/08/2024		200,000		200,227
Bank of New York Mellon Corp.
(3-month Secured Overnight Financing Rate + 0.26%),
0.40%, 04/26/2024		250,000		249,057
Citigroup, Inc.
(3-month USD LIBOR + 1.43%),
1.95%, 09/01/2023		250,000		250,891
Fifth Third Bancorp
2.60%, 06/15/2022		279,000		279,412
Goldman Sachs Group, Inc.
(3-month Secured Overnight Financing Rate + 0.54%),
0.74%, 11/17/2023		250,000		248,741
MUFG Union Bank NA
(3-month Secured Overnight Financing Rate + 0.71%),
0.96%, 12/09/2022		300,000		300,552
Royal Bank of Canada
(3-month Secured Overnight Financing Rate Index + 0.36%),
0.51%, 07/29/2024		250,000		248,430
Toronto-Dominion Bank
(3-month Secured Overnight Financing Rate + 0.24%),
0.34%, 01/06/2023		200,000		199,651

See accompanying notes.


Schedule of Investments
Principal Ultra-Short Active Income ETF
March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Banks (continued)
Truist Bank
2.45%, 08/01/2022 ^(b)	$	350,000	$	350,960
			$	2,327,921

Biotechnology — 2.16%
Gilead Sciences, Inc.
0.75%, 09/29/2023		188,000		183,604

Chemicals — 2.36%
Westlake Chemical Corp.
3.60%, 07/15/2022		200,000		200,329

Diversified Financial Services — 1.75%
AerCap Ireland Capital DAC/AerCap Global Aviation Trust
(3-month Secured Overnight Financing Rate + 0.68%),
0.95%, 09/29/2023		150,000		148,537

Electric — 10.40%
American Electric Power Co., Inc.
2.03%, 03/15/2024		200,000		196,536
Black Hills Corp.
1.04%, 08/23/2024		250,000		238,633
Dominion Energy, Inc.
(3-month USD LIBOR + 0.53%),
1.36%, 09/15/2023		150,000		149,728
Florida Power & Light Co.
(3-month Secured Overnight Financing Rate Index + 0.25%),
0.43%, 05/10/2023		100,000		99,744
NextEra Energy Capital Holdings, Inc.
(3-month Secured Overnight Financing Rate + 0.40%),
0.56%, 11/03/2023		200,000		199,177
			$	883,818

Entertainment — 1.19%
Magallanes, Inc.
2.04%, 03/15/2024		100,000		100,914

Healthcare — Products — 2.86%
PerkinElmer, Inc.
0.55%, 09/15/2023		250,000		242,756

Healthcare — Services — 2.87%
Humana, Inc.
0.65%, 08/03/2023		250,000		243,897

Household Products/Wares — 2.80%
Avery Dennison Corp.
0.85%, 08/15/2024		250,000		237,740

Insurance — 2.89%
Metropolitan Life Global Funding I
0.90%, 06/08/2023 ^(a)		250,000		245,651

Miscellaneous Manufacture — 2.94%
Siemens Financieringsmaatschappij NV
(3-month Secured Overnight Financing Rate + 0.43%),
0.68%, 03/11/2024 ^(a)		250,000		249,807

See accompanying notes.


	Schedule of Investments
	Principal Ultra-Short Active Income ETF
	March 31, 2022 (unaudited)

		Principal
BONDS (continued)		Amount		Value
Oil & Gas — 7.63%
ConocoPhillips Co.
2.13%, 03/08/2024	$	250,000	$	247,704
Suncor Energy, Inc.
2.80%, 05/15/2023		400,000		400,590
			$	648,294

Pipelines — 3.01%
ONEOK Partners LP
5.00%, 09/15/2023		250,000		256,072
Telecommunications — 6.73%
AT&T, Inc.
2.63%, 12/01/2022		221,000		222,063
NTT Finance Corp.
0.37%, 03/03/2023 ^(a)		200,000		196,996
Sprint Spectrum Co. LLC/Sprint Spectrum Co. II LLC/Sprint Spectrum Co. III
LLC
4.74%, 09/20/2029 ^(a)		150,000		153,150
			$	572,209
TOTAL BONDS			$	8,238,530


INVESTMENT COMPANIES — 3.41%		Shares Held		Value

Money Market Funds — 3.41%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(c),(d),(e),(f)}		48,293	$	48,293
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(f)		241,320		241,320
TOTAL INVESTMENT COMPANIES		$		289,613
Total Investments		$		8,528,143
Other Assets and Liabilities — (0.37)%				(31,812	)

Total Net Assets — 100.00%		$		8,496,331

^(a)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in
	transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these
	securities totaled $2,155,909 or 25.37% of net assets.
^(b)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $47,317 or
	0.56% of net assets.
^(c)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate
	as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(d)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of
	these securities totaled $48,293 or 0.57% of net assets.
^(e)	Non-income producing security.
^(f)	Current yield shown is as of period end.

See accompanying notes.


			Schedule of Investments
			Principal Ultra-Short Active Income ETF
			March 31, 2022 (unaudited)

Portfolio Summary (unaudited)
Sector					Percent
Financial					32.04	%
Asset Backed Securities					19.97	%
Consumer, Non-cyclical					10.69	%
Energy					10.64	%
Utilities					10.40	%
Communications					7.92	%
Money Market Funds					3.41	%
Industrial					2.94	%
Basic Materials					2.36	%
Other Assets and Liabilities					(0.37	)%
TOTAL NET ASSETS					100.00	%

			June 30, 2021		Purchases		Sales		March 31, 2022
Affiliated Securities			Value		Cost		Proceeds		Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$	1,936,880	$	1,888,587	$	48,293
		$	—	$	1,936,880	$	1,888,587	$	48,293

							Realized Gain
					Realized		from		Change in
					Gain/(Loss) on		Capital Gain		Unrealized
			Income ^(a)		Investments		Distributions		Gain/(Loss)
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$	— $		—	$	—
		$	—	$	— $		—	$	—

^(a)Amount excludes earnings from securities lending collateral.

See accompanying notes.


	Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS — 99.69%	Shares Held		Value

Advertising — 0.16%
Interpublic Group of Cos., Inc.	2,994	$	106,138
Omnicom Group, Inc.	631		53,559
		$	159,697

Aerospace & Defense — 1.46%
General Dynamics Corp.	862		207,897
L3Harris Technologies, Inc.	628		156,039
Lockheed Martin Corp.	959		423,302
Northrop Grumman Corp.	414		185,149
Raytheon Technologies Corp.	3,823		378,745
Teledyne Technologies, Inc. ^(a)	306		144,625
		$	1,495,757

Agriculture — 0.92%
Altria Group, Inc.	5,411		282,725
Archer-Daniels-Midland Co.	3,108		280,528
Philip Morris International, Inc.	4,029		378,484
		$	941,737

Apparel — 0.26%
NIKE, Inc., Class B	1,309		176,139
Tapestry, Inc.	1,239		46,029
Under Armour, Inc., Class C ^(a)	2,665		41,467
		$	263,635

Auto Manufacturers — 2.65%
Cummins, Inc.	445		91,274
Ford Motor Co.	11,139		188,360
PACCAR, Inc.	1,036		91,241
Tesla, Inc. ^(a)	2,186		2,355,634
		$	2,726,509

Banks — 3.21%
Bank of America Corp.	7,907		325,927
Bank of New York Mellon Corp.	1,468		72,857
Citigroup, Inc.	3,171		169,331
Citizens Financial Group, Inc.	2,348		106,435
Comerica, Inc.	596		53,896
Fifth Third Bancorp	2,868		123,439
First Republic Bank	359		58,194
Goldman Sachs Group, Inc.	379		125,108
JPMorgan Chase & Co.	7,018		956,694
KeyCorp	4,893		109,505
M&T Bank Corp.	351		59,494
Morgan Stanley	3,208		280,379
Northern Trust Corp.	575		66,959
Regions Financial Corp.	5,084		113,170
Signature Bank	364		106,830
State Street Corp.	818		71,264
SVB Financial Group ^(a)	111		62,099
Truist Financial Corp.	1,680		95,256
U.S. Bancorp	1,741		92,534
Wells Fargo & Co.	4,080		197,717
Zions Bancorp NA	795		52,120
		$	3,299,208

See accompanying notes.


	Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Beverages — 1.81%
Brown-Forman Corp., Class B	1,811	$	121,373
Coca-Cola Co.	12,867		797,754
Constellation Brands, Inc., Class A	442		101,802
Monster Beverage Corp. ^(a)	780		62,322
PepsiCo, Inc.	4,626		774,300
		$	1,857,551

Biotechnology — 1.25%
Amgen, Inc.	853		206,272
Bio-Rad Laboratories, Inc., Class A ^(a)	85		47,875
Corteva, Inc.	3,229		185,603
Gilead Sciences, Inc.	2,322		138,043
Incyte Corp. ^(a)	1,595		126,675
Regeneron Pharmaceuticals, Inc. ^(a)	500		349,210
Vertex Pharmaceuticals, Inc. ^(a)	897		234,090
		$	1,287,768

Building Materials — 0.37%
Carrier Global Corp.	1,691		77,566
Fortune Brands Home & Security, Inc.	524		38,923
Johnson Controls International PLC	1,698		111,338
Masco Corp.	1,321		67,371
Vulcan Materials Co.	468		85,971
		$	381,169

Chemicals — 1.36%
Air Products & Chemicals, Inc.	492		122,956
Albemarle Corp.	332		73,422
Celanese Corp.	339		48,433
CF Industries Holdings, Inc.	1,159		119,447
Dow, Inc.	1,724		109,853
Ecolab, Inc.	627		110,703
FMC Corp.	1,049		138,017
International Flavors & Fragrances, Inc.	754		99,023
Linde PLC	748		238,934
LyondellBasell Industries NV, Class A	550		56,551
Mosaic Co.	997		66,300
Sherwin-Williams Co.	844		210,679
		$	1,394,318

Commercial Services — 2.10%
Automatic Data Processing, Inc.	1,769		402,518
Cintas Corp.	411		174,835
Equifax, Inc.	547		129,694
FleetCor Technologies, Inc. ^(a)	217		54,046
Gartner, Inc. ^(a)	415		123,446
Global Payments, Inc.	503		68,831
MarketAxess Holdings, Inc.	129		43,886
Moody's Corp.	603		203,458
PayPal Holdings, Inc. ^(a)	1,303		150,692
Quanta Services, Inc.	466		61,330
Robert Half International, Inc.	895		102,191
Rollins, Inc.	1,262		44,233
S&P Global, Inc.	902		369,982
United Rentals, Inc. ^(a)	169		60,031
Verisk Analytics, Inc.	802		172,133
		$	2,161,306

See accompanying notes.


	Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Computers — 8.65%
Accenture PLC, Class A	1,259	$	424,573
Apple, Inc.	41,769		7,293,285
Cognizant Technology Solutions Corp., Class A	2,933		263,002
DXC Technology Co. ^(a)	1,613		52,632
EPAM Systems, Inc. ^(a)	218		64,661
Fortinet, Inc. ^(a)	494		168,819
Hewlett Packard Enterprise Co.	3,654		61,058
HP, Inc.	2,112		76,666
International Business Machines Corp.	2,480		322,450
NetApp, Inc.	1,287		106,821
Seagate Technology Holdings PLC	657		59,064
		$	8,893,031

Distribution/Wholesale — 0.69%
Copart, Inc. ^(a)	475		59,598
Fastenal Co.	4,033		239,560
LKQ Corp.	2,203		100,038
Pool Corp.	244		103,176
WW Grainger, Inc.	403		207,863
		$	710,235

Diversified Financial Services — 3.17%
American Express Co.	1,466		274,142
Ameriprise Financial, Inc.	466		139,968
BlackRock, Inc.	402		307,196
Capital One Financial Corp.	610		80,087
Cboe Global Markets, Inc.	1,083		123,917
Charles Schwab Corp.	3,375		284,546
CME Group, Inc.	1,111		264,262
Discover Financial Services	1,218		134,211
Franklin Resources, Inc.	1,503		41,964
Intercontinental Exchange, Inc.	2,571		339,681
Invesco Ltd.	2,010		46,351
Mastercard, Inc., Class A	883		315,567
Nasdaq, Inc.	1,131		201,544
Raymond James Financial, Inc.	1,106		121,560
Synchrony Financial	1,432		49,848
T Rowe Price Group, Inc.	434		65,616
Visa, Inc., Class A	2,113		468,600
		$	3,259,060

Electric — 3.67%
AES Corp.	3,281		84,420
Alliant Energy Corp.	2,135		133,395
Ameren Corp.	1,623		152,173
American Electric Power Co., Inc.	1,990		198,542
CenterPoint Energy, Inc.	4,696		143,886
CMS Energy Corp.	2,064		144,356
Consolidated Edison, Inc.	1,779		168,436
Dominion Energy, Inc.	2,732		232,138
DTE Energy Co.	1,153		152,438
Duke Energy Corp.	3,323		371,046
Edison International	2,256		158,146
Entergy Corp.	1,299		151,658
Evergy, Inc.	2,711		185,270
Eversource Energy	1,046		92,247
Exelon Corp.	4,121		196,283

See accompanying notes.


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Electric (continued)
FirstEnergy Corp.	3,295	$	151,109
Pinnacle West Capital Corp.	893		69,743
PPL Corp.	2,972		84,880
Public Service Enterprise Group, Inc.	2,467		172,690
Sempra Energy	1,241		208,637
Southern Co.	3,432		248,854
WEC Energy Group, Inc.	940		93,821
Xcel Energy, Inc.	2,431		175,445
		$	3,769,613

Electrical Components & Equipment — 0.40%
AMETEK, Inc.	1,162		154,755
Emerson Electric Co.	2,104		206,297
Generac Holdings, Inc. ^(a)	178		52,913
		$	413,965

Electronics — 1.19%
Agilent Technologies, Inc.	1,268		167,794
Allegion PLC	997		109,451
Amphenol Corp., Class A	3,426		258,149
Fortive Corp.	1,393		84,876
Garmin Ltd.	1,119		132,725
Honeywell International, Inc.	1,045		203,336
Keysight Technologies, Inc. ^(a)	388		61,292
Mettler-Toledo International, Inc. ^(a)	100		137,319
TE Connectivity Ltd.	536		70,205
		$	1,225,147

Engineering & Construction — 0.08%
Jacobs Engineering Group, Inc.	596		82,135

Entertainment — 0.06%
Live Nation Entertainment, Inc. ^(a)	504		59,291

Environmental Control — 0.50%
Republic Services, Inc.	1,621		214,782
Waste Management, Inc.	1,914		303,369
		$	518,151

Food — 1.70%
Campbell Soup Co.	1,571		70,020
Conagra Brands, Inc.	2,410		80,904
General Mills, Inc.	2,738		185,417
Hershey Co.	1,046		226,595
Hormel Foods Corp.	1,432		73,805
J M Smucker Co.	981		132,837
Kellogg Co.	1,231		79,387
Kraft Heinz Co.	2,286		90,046
Kroger Co.	1,312		75,270
McCormick & Co., Inc.	1,503		149,999
Mondelez International, Inc., Class A	5,999		376,617
Tyson Foods, Inc., Class A	2,326		208,479
		$	1,749,376

Forest Products & Paper — 0.08%
International Paper Co.	1,764		81,409

Gas — 0.26%
Atmos Energy Corp.	1,128		134,785

See accompanying notes.


	Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Gas (continued)
NiSource, Inc.	4,097	$	130,284
		$	265,069

Hand/Machine Tools — 0.16%
Snap-on, Inc.	551		113,219
Stanley Black & Decker, Inc.	368		51,443
		$	164,662

Healthcare — Products — 4.46%
Abbott Laboratories	4,101		485,394
Align Technology, Inc. ^(a)	146		63,656
Baxter International, Inc.	1,276		98,941
Bio-Techne Corp.	115		49,800
Boston Scientific Corp. ^(a)	4,858		215,161
Cooper Cos., Inc.	339		141,563
Danaher Corp.	2,246		658,819
Edwards Lifesciences Corp. ^(a)	1,755		206,599
Henry Schein, Inc. ^(a)	1,977		172,375
Hologic, Inc. ^(a)	1,092		83,887
IDEXX Laboratories, Inc. ^(a)	137		74,947
Intuitive Surgical, Inc. ^(a)	411		123,990
Medtronic PLC	3,395		376,675
PerkinElmer, Inc.	673		117,412
ResMed, Inc.	561		136,048
STERIS PLC	641		154,975
Stryker Corp.	999		267,083
Teleflex, Inc.	141		50,031
Thermo Fisher Scientific, Inc.	1,325		782,611
Waters Corp. ^(a)	593		184,061
West Pharmaceutical Services, Inc.	339		139,231
		$	4,583,259

Healthcare — Services — 2.70%
Anthem, Inc.	940		461,747
Catalent, Inc. ^(a)	497		55,117
Centene Corp. ^(a)	986		83,011
Charles River Laboratories International, Inc. ^(a)	178		50,547
DaVita, Inc. ^(a)	589		66,622
HCA Healthcare, Inc.	676		169,419
IQVIA Holdings, Inc. ^(a)	671		155,142
Laboratory Corp. of America Holdings ^(a)	526		138,685
Molina Healthcare, Inc. ^(a)	188		62,715
Quest Diagnostics, Inc.	905		123,858
UnitedHealth Group, Inc.	2,540		1,295,324
Universal Health Services, Inc., Class B	747		108,278
		$	2,770,465

Home Builders — 0.19%
DR Horton, Inc.	693		51,635
Lennar Corp., Class A	623		50,569
NVR, Inc. ^(a)	11		49,140
PulteGroup, Inc.	952		39,889
		$	191,233

Household Products — 1.41%
Colgate-Palmolive Co.	2,814		213,386
Estee Lauder Cos., Inc., Class A	320		87,142

See accompanying notes.


	Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Household Products (continued)
Procter & Gamble Co.	7,480	$	1,142,944
		$	1,443,472

Household Products/Wares — 0.35%
Avery Dennison Corp.	280		48,712
Church & Dwight Co., Inc.	2,067		205,418
Kimberly-Clark Corp.	846		104,193
		$	358,323

Insurance — 5.75%
Aflac, Inc.	2,812		181,065
Allstate Corp.	771		106,791
American International Group, Inc.	1,421		89,196
Aon PLC, Class A	751		244,548
Arthur J Gallagher & Co.	1,037		181,060
Assurant, Inc.	943		171,466
Berkshire Hathaway, Inc., Class B ^(a)	5,340		1,884,539
Brown & Brown, Inc.	2,778		200,766
Chubb Ltd.	1,819		389,084
Cincinnati Financial Corp.	1,512		205,571
Everest Re Group Ltd.	602		181,431
Globe Life, Inc.	1,123		112,974
Hartford Financial Services Group, Inc.	2,137		153,458
Lincoln National Corp.	1,558		101,831
Loews Corp.	2,022		131,066
Marsh & McLennan Cos., Inc.	2,246		382,763
MetLife, Inc.	2,894		203,390
Progressive Corp.	2,044		232,996
Prudential Financial, Inc.	1,340		158,348
Travelers Cos., Inc.	1,434		262,035
W R Berkley Corp.	2,706		180,193
Willis Towers Watson PLC	645		152,362
		$	5,906,933

Internet — 9.71%
Alphabet, Inc., Class A ^(a)	806		2,241,768
Alphabet, Inc., Class C ^(a)	751		2,097,536
Amazon.com, Inc. ^(a)	1,169		3,810,882
CDW Corp.	316		56,529
Etsy, Inc. ^(a)	391		48,593
Meta Platforms, Inc., Class A ^(a)	6,370		1,416,433
Netflix, Inc. ^(a)	458		171,562
NortonLifeLock, Inc.	2,028		53,783
VeriSign, Inc. ^(a)	382		84,980
		$	9,982,066

Iron & Steel — 0.15%
Nucor Corp.	1,032		153,407

Lodging — 0.16%
Hilton Worldwide Holdings, Inc. ^(a)	526		79,815
Marriott International, Inc., Class A ^(a)	489		85,942
		$	165,757

Machinery — Diversified — 0.94%
Deere & Co.	318		132,117
Dover Corp.	1,280		200,832
IDEX Corp.	629		120,598

See accompanying notes.


	Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Machinery — Diversified (continued)
Nordson Corp.	528	$	119,898
Otis Worldwide Corp.	2,178		167,597
Rockwell Automation, Inc.	572		160,177
Westinghouse Air Brake Technologies Corp.	640		61,549
		$	962,768

Media — 0.93%
Charter Communications, Inc., Class A ^(a)	397		216,572
Comcast Corp., Class A	10,537		493,342
FactSet Research Systems, Inc.	428		185,816
Fox Corp., Class B	1,738		63,055
		$	958,785

Mining — 0.19%
Freeport-McMoRan, Inc.	2,093		104,106
Newmont Corp.	1,199		95,260
		$	199,366

Miscellaneous Manufacture — 0.98%
3M Co.	1,725		256,818
AO Smith Corp.	1,648		105,291
Eaton Corp. PLC	813		123,381
Illinois Tool Works, Inc.	984		206,050
Parker-Hannifin Corp.	577		163,729
Textron, Inc.	798		59,355
Trane Technologies PLC	636		97,117
		$	1,011,741

Office & Business Equipment — 0.05%
Zebra Technologies Corp., Class A ^(a)	132		54,608

Oil & Gas — 2.84%
APA Corp.	1,393		57,573
Chevron Corp.	5,206		847,693
ConocoPhillips	1,492		149,200
Coterra Energy, Inc.	2,335		62,975
Devon Energy Corp.	1,238		73,203
Diamondback Energy, Inc.	870		119,260
EOG Resources, Inc.	840		100,153
Exxon Mobil Corp.	11,424		943,508
Hess Corp.	678		72,573
Marathon Oil Corp.	2,487		62,449
Marathon Petroleum Corp.	1,041		89,005
Occidental Petroleum Corp.	1,458		82,727
Pioneer Natural Resources Co.	700		175,021
Valero Energy Corp.	793		80,521
		$	2,915,861

Oil & Gas Services — 0.22%
Baker Hughes Co.	1,843		67,104
Halliburton Co.	1,869		70,779
Schlumberger NV	2,131		88,031
		$	225,914

Packaging & Containers — 0.39%
Amcor PLC	6,874		77,882
Ball Corp.	1,681		151,290
Packaging Corp. of America	788		123,015

See accompanying notes.


	Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Packaging & Containers (continued)
Sealed Air Corp.	790	$	52,898
		$	405,085

Pharmaceuticals — 5.79%
AbbVie, Inc.	5,688		922,082
AmerisourceBergen Corp.	972		150,378
Becton Dickinson & Co.	932		247,912
Bristol-Myers Squibb Co.	8,006		584,678
Cardinal Health, Inc.	1,390		78,813
Cigna Corp.	607		145,443
CVS Health Corp.	3,428		346,948
Eli Lilly & Co.	1,559		446,451
Johnson & Johnson	6,369		1,128,778
McKesson Corp.	639		195,617
Merck & Co., Inc.	8,580		703,989
Organon & Co.	1,406		49,111
Pfizer, Inc.	11,013		570,143
Zoetis, Inc.	1,986		374,540
		$	5,944,883

Pipelines — 0.41%
Kinder Morgan, Inc.	9,178		173,556
ONEOK, Inc.	1,015		71,689
Williams Cos., Inc.	5,409		180,715
		$	425,960

Real Estate — 0.13%
CBRE Group, Inc., Class A ^(a)	1,426		130,508

REITs — 4.45%
Alexandria Real Estate Equities, Inc.	790		158,988
American Tower Corp.	1,237		310,759
AvalonBay Communities, Inc.	676		167,898
Boston Properties, Inc.	1,079		138,975
Crown Castle International Corp.	1,333		246,072
Digital Realty Trust, Inc.	1,206		171,011
Duke Realty Corp.	2,583		149,969
Equinix, Inc.	181		134,233
Equity Residential	1,789		160,867
Essex Property Trust, Inc.	415		143,374
Extra Space Storage, Inc.	1,042		214,235
Federal Realty Investment Trust	977		119,262
Healthpeak Properties, Inc.	2,338		80,264
Iron Mountain, Inc.	2,005		111,097
Kimco Realty Corp.	2,313		57,131
Mid-America Apartment Communities, Inc.	952		199,396
Prologis, Inc.	2,885		465,870
Public Storage	777		303,248
Realty Income Corp.	2,586		179,210
Regency Centers Corp.	1,785		127,342
SBA Communications Corp.	714		245,687
Simon Property Group, Inc.	595		78,278
UDR, Inc.	2,310		132,525
Ventas, Inc.	1,397		86,279
Welltower, Inc.	1,914		184,012
Weyerhaeuser Co.	5,405		204,849
		$	4,570,831

See accompanying notes.


	Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Retail — 5.04%
Advance Auto Parts, Inc.	609	$	126,039
AutoZone, Inc. ^(a)	126		257,617
Best Buy Co., Inc.	548		49,813
Chipotle Mexican Grill, Inc. ^(a)	43		68,027
Costco Wholesale Corp.	1,454		837,286
Darden Restaurants, Inc.	374		49,723
Dollar General Corp.	881		196,137
Dollar Tree, Inc. ^(a)	477		76,392
Domino's Pizza, Inc.	116		47,213
Genuine Parts Co.	1,019		128,414
Home Depot, Inc.	3,277		980,904
Lowe's Cos., Inc.	2,490		503,453
McDonald's Corp.	1,838		454,501
O'Reilly Automotive, Inc. ^(a)	379		259,600
Ross Stores, Inc.	683		61,784
Starbucks Corp.	1,946		177,028
Target Corp.	563		119,480
Tractor Supply Co.	527		122,986
Ulta Beauty, Inc. ^(a)	300		119,466
Walgreens Boots Alliance, Inc.	1,971		88,242
Walmart, Inc.	1,916		285,331
Yum! Brands, Inc.	1,406		166,653
		$	5,176,089

Savings & Loans — 0.09%
People's United Financial, Inc.	4,528		90,515

Semiconductors — 3.75%
Advanced Micro Devices, Inc. ^(a)	3,359		367,273
Applied Materials, Inc.	1,008		132,854
Broadcom, Inc.	804		506,263
KLA Corp.	488		178,637
Lam Research Corp.	190		102,146
Microchip Technology, Inc.	946		71,083
Monolithic Power Systems, Inc.	262		127,248
NVIDIA Corp.	6,723		1,834,438
NXP Semiconductors NV	412		76,253
QUALCOMM, Inc.	1,176		179,716
Skyworks Solutions, Inc.	407		54,245
Teradyne, Inc.	458		54,149
Texas Instruments, Inc.	941		172,655
		$	3,856,960

Shipbuilding — 0.06%
Huntington Ingalls Industries, Inc.	324		64,619

Software — 8.49%
Adobe, Inc. ^(a)	466		212,319
Akamai Technologies, Inc. ^(a)	1,153		137,657
ANSYS, Inc. ^(a)	187		59,400
Broadridge Financial Solutions, Inc.	856		133,288
Cadence Design Systems, Inc. ^(a)	464		76,309
Cerner Corp.	1,620		151,567
Electronic Arts, Inc.	769		97,286
Intuit, Inc.	633		304,372
Jack Henry & Associates, Inc.	937		184,636
Microsoft Corp.	20,147		6,211,521
Oracle Corp.	3,579		296,091
Paychex, Inc.	1,977		269,801

See accompanying notes.


	Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Software (continued)
Paycom Software, Inc. ^(a)	155	$	53,689
PTC, Inc. ^(a)	417		44,919
Roper Technologies, Inc.	246		116,169
salesforce.com, Inc. ^(a)	955		202,766
Synopsys, Inc. ^(a)	508		169,301
		$	8,721,091

Telecommunications — 1.96%
Arista Networks, Inc. ^(a)	1,014		140,926
AT&T, Inc.	10,071		237,978
Cisco Systems, Inc.	13,895		774,785
Corning, Inc.	1,570		57,949
Juniper Networks, Inc.	3,636		135,114
Motorola Solutions, Inc.	768		186,009
Verizon Communications, Inc.	9,450		481,383
		$	2,014,144

Toys, Games & Hobbies — 0.04%
Hasbro, Inc.	505		41,370

Transportation — 1.75%
CH Robinson Worldwide, Inc.	445		47,931
CSX Corp.	4,012		150,249
Expeditors International of Washington, Inc.	1,236		127,506
FedEx Corp.	357		82,606
JB Hunt Transport Services, Inc.	905		181,715
Norfolk Southern Corp.	474		135,194
Old Dominion Freight Line, Inc.	408		121,862
Union Pacific Corp.	2,263		618,274
United Parcel Service, Inc., Class B	1,545		331,341
		$	1,796,678

Water — 0.15%
American Water Works Co., Inc.	938		155,267
TOTAL COMMON STOCKS		$	102,437,757

See accompanying notes.


INVESTMENT COMPANIES — 0.24%		Shares Held		Value
Money Market Fund — 0.24%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(b)		246,900	$	246,900
TOTAL INVESTMENT COMPANIES			$	246,900
Total Investments			$	102,684,657
Other Assets and Liabilities — 0.07%				68,736
Total Net Assets — 100.00%			$	102,753,393

^(a)	Non-income producing security.
^(b)	Current yield shown is as of period end.

Schedule of Investments

Principal U.S. Large-Cap Adaptive Multi-Factor ETF

March 31, 2022 (unaudited)


Portfolio Summary (unaudited)

Sector	Percent
Consumer, Non-cyclical	22.48	%
Technology	20.95	%
Financial	16.80	%
Communications	12.76	%
Consumer, Cyclical	9.08	%
Industrial	8.29	%
Utilities	4.08	%
Energy	3.47	%
Basic Materials	1.78	%
Money Market Fund	0.24	%
Other Assets and Liabilities	0.07	%
TOTAL NET ASSETS	100.00	%

See accompanying notes.


	Schedule of Investments
	Principal U.S. Mega-Cap ETF
	March 31, 2022 (unaudited)

COMMON STOCKS — 99.61%		Shares Held		Value
Auto Manufacturers — 1.65%
Tesla, Inc. ^(a)		25,079	$	27,025,130
Banks — 4.18%
Bank of America Corp.		459,737		18,950,359
JPMorgan Chase & Co.		212,824		29,012,167
Wells Fargo & Co.		420,558		20,380,241
			$	68,342,767

Beverages — 7.05%
Coca-Cola Co.		958,969		59,456,078
PepsiCo, Inc.		334,542		55,995,640
			$	115,451,718

Commercial Services — 0.53%
PayPal Holdings, Inc. ^(a)		75,125		8,688,206
Computers — 9.08%
Accenture PLC, Class A		109,256		36,844,401
Apple, Inc.		640,059		111,760,702
			$	148,605,103

Diversified Financial Services — 4.31%
Mastercard, Inc., Class A		100,240		35,823,771
Visa, Inc., Class A		156,422		34,689,707
			$	70,513,478

Healthcare — Products — 6.40%
Abbott Laboratories		295,734		35,003,076
Danaher Corp.		114,810		33,677,217
Thermo Fisher Scientific, Inc.		61,127		36,104,663
			$	104,784,956

Healthcare — Services — 2.79%
UnitedHealth Group, Inc.		89,390		45,586,218
Household Products — 3.36%
Procter & Gamble Co.		359,916		54,995,165
Insurance — 3.97%
Berkshire Hathaway, Inc., Class B ^(a)		184,350		65,058,959
Internet — 6.41%
Alphabet, Inc., Class A ^(a)		13,048		36,291,055
Amazon.com, Inc. ^(a)		10,626		34,640,229
Meta Platforms, Inc., Class A ^(a)		57,084		12,693,198
Netflix, Inc. ^(a)		56,929		21,325,034
			$	104,949,516

Media — 3.51%
Comcast Corp., Class A		622,544		29,147,510
Walt Disney Co. ^(a)		205,977		28,251,805
			$	57,399,315

Oil & Gas — 3.59%
Chevron Corp.		192,460		31,338,262
Exxon Mobil Corp.		331,806		27,403,857
			$	58,742,119

See accompanying notes.


	Schedule of Investments
	Principal U.S. Mega-Cap ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value
Pharmaceuticals — 12.99%
AbbVie, Inc.		323,604	$	52,459,445
Eli Lilly & Co.		151,238		43,310,026
Johnson & Johnson		311,571		55,219,728
Merck & Co., Inc.		464,031		38,073,744
Pfizer, Inc.		454,090		23,508,239
			$	212,571,182

Retail — 7.97%
Costco Wholesale Corp.		77,752		44,773,489
Home Depot, Inc.		106,398		31,848,114
Walmart, Inc.		360,999		53,759,971
			$	130,381,574

Semiconductors — 6.32%
Broadcom, Inc.		72,003		45,338,849
Intel Corp.		653,747		32,399,701
NVIDIA Corp.		94,276		25,724,150
			$	103,462,700

Software — 7.72%
Adobe, Inc. ^(a)		60,589		27,605,560
Microsoft Corp.		123,933		38,209,783
Oracle Corp.		401,019		33,176,302
salesforce.com, Inc. ^(a)		128,536		27,290,764
			$	126,282,409

Telecommunications — 7.78%
AT&T, Inc.		1,862,916		44,020,705
Cisco Systems, Inc.		641,956		35,795,467
Verizon Communications, Inc.		931,627		47,457,079
			$	127,273,251
TOTAL COMMON STOCKS			$	1,630,113,766


INVESTMENT COMPANIES — 0.33%				Shares Held		Value

Money Market Fund — 0.33%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(b)				5,339,042	$	5,339,042
TOTAL INVESTMENT COMPANIES					$	5,339,042
Total Investments					$	1,635,452,808
Other Assets and Liabilities — 0.06%						1,051,139
Total Net Assets — 100.00%					$	1,636,503,947

^(a)	Non-income producing security.
^(b)	Current yield shown is as of period end.

	Portfolio Summary (unaudited)
Sector		Percent
Consumer, Non-cyclical		33.12	%
Technology		23.12	%
Communications		17.70	%
Financial		12.46	%
Consumer, Cyclical		9.62	%
Energy		3.59	%
Money Market Fund		0.33	%
Other Assets and Liabilities		0.06	%
TOTAL NET ASSETS		100.00	%

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS — 99.61%	Shares Held		Value

Aerospace & Defense — 1.21%
AAR Corp. ^(a)	315	$	15,255
Aerojet Rocketdyne Holdings, Inc. ^(a)	220		8,657
Barnes Group, Inc.	221		8,882
Kaman Corp.	173		7,522
Moog, Inc., Class A	217		19,053
National Presto Industries, Inc.	67		5,156
Park Aerospace Corp.	366		4,776
Triumph Group, Inc. ^(a)	263		6,649
		$	75,950

Agriculture — 0.90%
Andersons, Inc.	438		22,014
Fresh Del Monte Produce, Inc.	263		6,814
Universal Corp.	246		14,285
Vector Group Ltd.	1,116		13,437
		$	56,550

Apparel — 0.71%
Oxford Industries, Inc.	160		14,480
Steven Madden Ltd.	771		29,791
		$	44,271

Auto Parts & Equipment — 1.33%
Dorman Products, Inc. ^(a)	203		19,291
Gentherm, Inc. ^(a)	108		7,888
Meritor, Inc. ^(a)	219		7,790
Methode Electronics, Inc.	340		14,705
Motorcar Parts of America, Inc. ^(a)	219		3,905
Standard Motor Products, Inc.	367		15,833
Titan International, Inc. ^(a)	648		9,545
XPEL, Inc. ^(a)	84		4,419
		$	83,376

Banks — 15.30%
Allegiance Bancshares, Inc.	357		15,951
Ameris Bancorp	447		19,614
BancFirst Corp.	260		21,635
Bancorp, Inc. ^(a)	447		12,663
BankUnited, Inc.	570		25,057
Banner Corp.	393		23,002
Central Pacific Financial Corp.	556		15,512
City Holding Co.	229		18,022
Columbia Banking System, Inc.	551		17,781
Community Bank System, Inc.	347		24,342
Customers Bancorp, Inc. ^(a)	226		11,784
CVB Financial Corp.	1,275		29,593
Dime Community Bancshares, Inc.	524		18,115
Eagle Bancorp, Inc.	384		21,892
FB Financial Corp.	463		20,566
First Bancorp	461		19,256
First BanCorp	1,269		16,649
First Commonwealth Financial Corp.	1,279		19,390
First Financial Bancorp	1,052		24,249
First Hawaiian, Inc.	853		23,790
Flagstar Bancorp, Inc.	404		17,130
Hanmi Financial Corp.	624		15,357
Heritage Financial Corp.	448		11,227
Hilltop Holdings, Inc.	296		8,702

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Banks (continued)
HomeStreet, Inc.	339	$	16,062
Hope Bancorp, Inc.	1,403		22,560
Independent Bank Corp.	304		24,834
Independent Bank Group, Inc.	372		26,472
Lakeland Financial Corp.	298		21,754
Meta Financial Group, Inc.	243		13,346
National Bank Holdings Corp., Class A	444		17,884
NBT Bancorp, Inc.	550		19,871
OFG Bancorp	705		18,781
Park National Corp.	171		22,466
Preferred Bank	229		16,967
Renasant Corp.	455		15,220
S&T Bancorp, Inc.	594		17,571
Seacoast Banking Corp. of Florida	468		16,389
ServisFirst Bancshares, Inc.	433		41,261
Simmons First National Corp., Class A	766		20,085
Southside Bancshares, Inc.	455		18,578
Tompkins Financial Corp.	146		11,427
Triumph Bancorp, Inc. ^(a)	156		14,667
TrustCo Bank Corp.	179		5,715
Trustmark Corp.	509		15,468
United Community Banks, Inc.	953		33,164
Veritex Holdings, Inc.	573		21,871
Walker & Dunlop, Inc.	269		34,814
Westamerica BanCorp	341		20,630
		$	959,136

Beverages — 0.75%
Celsius Holdings, Inc. ^(a)	143		7,891
Coca-Cola Consolidated, Inc.	16		7,949
MGP Ingredients, Inc.	218		18,659
National Beverage Corp.	289		12,571
		$	47,070

Biotechnology — 0.56%
ANI Pharmaceuticals, Inc. ^(a)	108		3,036
Avid Bioservices, Inc. ^(a)	289		5,887
Emergent BioSolutions, Inc. ^(a)	173		7,103
Innoviva, Inc. ^(a)	571		11,049
iTeos Therapeutics, Inc. ^(a)	127		4,087
Organogenesis Holdings, Inc. ^(a)	522		3,978
		$	35,140

Building Materials — 1.78%
AAON, Inc.	319		17,778
Apogee Enterprises, Inc.	117		5,553
Boise Cascade Co.	231		16,048
Griffon Corp.	547		10,956
PGT Innovations, Inc. ^(a)	614		11,040
SPX Corp. ^(a)	205		10,129
UFP Industries, Inc.	521		40,200
		$	111,704

Chemicals — 3.95%
AdvanSix, Inc.	239		12,211
American Vanguard Corp.	544		11,054
Balchem Corp.	287		39,233
Ferro Corp. ^(a)	712		15,479

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Chemicals (continued)
GCP Applied Technologies, Inc. ^(a)	477	$	14,987
Hawkins, Inc.	248		11,383
HB Fuller Co.	501		33,101
Innospec, Inc.	189		17,492
Koppers Holdings, Inc.	150		4,128
Quaker Chemical Corp.	105		18,145
Rogers Corp. ^(a)	158		42,929
Stepan Co.	171		16,896
Trinseo PLC	140		6,709
Unifi, Inc. ^(a)	203		3,674
		$	247,421

Coal — 0.27%
CONSOL Energy, Inc. ^(a)	158		5,946
SunCoke Energy, Inc.	531		4,731
Warrior Met Coal, Inc.	173		6,420
		$	17,097

Commercial Services — 3.31%
ABM Industries, Inc.	264		12,155
Alarm.com Holdings, Inc. ^(a)	324		21,533
AMN Healthcare Services, Inc. ^(a)	246		25,665
Arlo Technologies, Inc. ^(a)	491		4,350
CoreCivic, Inc. ^(a)	594		6,635
CorVel Corp. ^(a)	92		15,497
Cross Country Healthcare, Inc. ^(a)	235		5,092
Deluxe Corp.	250		7,560
EVERTEC, Inc.	453		18,541
Forrester Research, Inc. ^(a)	281		15,854
Heidrick & Struggles International, Inc.	288		11,399
Korn Ferry	362		23,508
Medifast, Inc.	39		6,660
Monro, Inc.	131		5,809
Perdoceo Education Corp. ^(a)	585		6,716
Resources Connection, Inc.	868		14,878
TrueBlue, Inc. ^(a)	190		5,489
		$	207,341

Computers — 1.69%
Corsair Gaming, Inc. ^(a)	223		4,719
ExlService Holdings, Inc. ^(a)	298		42,694
Insight Enterprises, Inc. ^(a)	322		34,557
NetScout Systems, Inc. ^(a)	565		18,125
TTEC Holdings, Inc.	74		6,107
		$	106,202

Distribution/Wholesale — 0.62%
G-III Apparel Group Ltd. ^(a)	211		5,707
Resideo Technologies, Inc. ^(a)	394		9,389
ScanSource, Inc. ^(a)	483		16,804
Veritiv Corp. ^(a)	54		7,214
		$	39,114

Diversified Financial Services — 2.96%
B Riley Financial, Inc.	160		11,194
Blucora, Inc. ^(a)	632		12,356
Brightsphere Investment Group, Inc.	401		9,724

See accompanying notes.


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Diversified Financial Services (continued)
Encore Capital Group, Inc. ^(a)	335	$	21,015
Enova International, Inc. ^(a)	326		12,378
EZCORP, Inc., Class A ^(a)	679		4,101
Greenhill & Co., Inc.	444		6,869
LendingTree, Inc. ^(a)	53		6,342
Mr Cooper Group, Inc. ^(a)	416		18,999
Piper Sandler Cos.	177		23,231
PRA Group, Inc. ^(a)	369		16,634
StoneX Group, Inc. ^(a)	261		19,374
Virtus Investment Partners, Inc.	28		6,720
WisdomTree Investments, Inc.	1,912		11,223
World Acceptance Corp. ^(a)	28		5,372
		$	185,532

Electric — 0.59%
Avista Corp.	477		21,537
Unitil Corp.	306		15,263
		$	36,800

Electrical Components & Equipment — 0.37%
Encore Wire Corp.	127		14,487
Insteel Industries, Inc.	237		8,767
		$	23,254

Electronics — 2.36%
Advanced Energy Industries, Inc.	108		9,297
Badger Meter, Inc.	208		20,740
Benchmark Electronics, Inc.	258		6,460
Brady Corp., Class A	227		10,503
CTS Corp.	361		12,758
Knowles Corp. ^(a)	1,081		23,274
Mesa Laboratories, Inc.	53		13,509
OSI Systems, Inc. ^(a)	165		14,045
Plexus Corp. ^(a)	215		17,589
Sanmina Corp. ^(a)	272		10,994
TTM Technologies, Inc. ^(a)	603		8,936
		$	148,105

Energy — Alternate Sources — 0.10%
Green Plains, Inc. ^(a)	205		6,357

Engineering & Construction — 1.70%
Comfort Systems USA, Inc.	349		31,064
Exponent, Inc.	312		33,712
Granite Construction, Inc.	253		8,298
MYR Group, Inc. ^(a)	220		20,689
NV5 Global, Inc. ^(a)	95		12,664
		$	106,427

Entertainment — 0.35%
Golden Entertainment, Inc. ^(a)	193		11,207
Monarch Casino & Resort, Inc. ^(a)	126		10,991
		$	22,198

Environmental Control — 0.10%
U.S. Ecology, Inc. ^(a)	127		6,081

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Food — 2.52%
B&G Foods, Inc.	332	$	8,957
Cal-Maine Foods, Inc.	339		18,720
Hostess Brands, Inc. ^(a)	1,395		30,606
J & J Snack Foods Corp.	116		17,992
John B Sanfilippo & Son, Inc.	78		6,508
Seneca Foods Corp., Class A ^(a)	105		5,412
Simply Good Foods Co. ^(a)	833		31,612
SpartanNash Co.	575		18,969
Tootsie Roll Industries, Inc.	308		10,768
United Natural Foods, Inc. ^(a)	199		8,229
		$	157,773

Food Service — 0.13%
Healthcare Services Group, Inc.	442		8,208

Forest Products & Paper — 0.35%
Glatfelter Corp.	459		5,682
Mercer International, Inc.	690		9,626
Schweitzer-Mauduit International, Inc.	230		6,325
		$	21,633

Gas — 0.77%
Chesapeake Utilities Corp.	131		18,046
Northwest Natural Holding Co.	386		19,964
South Jersey Industries, Inc.	303		10,469
		$	48,479

Hand/Machine Tools — 0.48%
Enerpac Tool Group Corp.	376		8,230
Franklin Electric Co., Inc.	267		22,172
		$	30,402

Healthcare — Products — 2.74%
CONMED Corp.	264		39,217
Cutera, Inc. ^(a)	107		7,383
Hanger, Inc. ^(a)	322		5,902
Integer Holdings Corp. ^(a)	138		11,119
Lantheus Holdings, Inc. ^(a)	191		10,564
LeMaitre Vascular, Inc.	259		12,036
Meridian Bioscience, Inc. ^(a)	415		10,773
Merit Medical Systems, Inc. ^(a)	341		22,683
Omnicell, Inc. ^(a)	248		32,114
Orthofix Medical, Inc. ^(a)	185		6,050
Varex Imaging Corp. ^(a)	484		10,304
Zynex, Inc.	631		3,931
		$	172,076

Healthcare — Services — 1.70%
Addus HomeCare Corp. ^(a)	70		6,530
Community Health Systems, Inc. ^(a)	513		6,089
Ensign Group, Inc.	319		28,713
Fulgent Genetics, Inc. ^(a)	94		5,866
Joint Corp. ^(a)	121		4,282
MEDNAX, Inc. ^(a)	402		9,439
Pennant Group, Inc. ^(a)	266		4,956
RadNet, Inc. ^(a)	232		5,190
Select Medical Holdings Corp.	328		7,869
Tivity Health, Inc. ^(a)	447		14,380

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Healthcare — Services (continued)
U.S. Physical Therapy, Inc.	135	$	13,426
		$	106,740

Home Builders — 1.06%
Cavco Industries, Inc. ^(a)	57		13,728
Century Communities, Inc.	107		5,732
Installed Building Products, Inc.	75		6,337
LCI Industries	75		7,786
LGI Homes, Inc. ^(a)	66		6,447
M/I Homes, Inc. ^(a)	118		5,233
MDC Holdings, Inc.	178		6,736
Meritage Homes Corp. ^(a)	103		8,161
Winnebago Industries, Inc.	116		6,267
		$	66,427

Home Furnishings — 0.21%
Ethan Allen Interiors, Inc.	327		8,525
Sleep Number Corp. ^(a)	94		4,767
		$	13,292

Household Products — 0.67%
Edgewell Personal Care Co.	194		7,114
elf Beauty, Inc. ^(a)	524		13,535
Inter Parfums, Inc.	243		21,396
		$	42,045

Household Products/Wares — 0.83%
Central Garden & Pet Co., Class A ^(a)	362		14,762
Central Garden & Pet Co. ^(a)	214		9,408
Quanex Building Products Corp.	472		9,907
WD-40 Co.	99		18,140
		$	52,217

Insurance — 2.63%
American Equity Investment Life Holding Co.	240		9,578
AMERISAFE, Inc.	141		7,004
Assured Guaranty Ltd.	447		28,456
Employers Holdings, Inc.	313		12,839
Genworth Financial, Inc., Class A ^(a)	1,832		6,925
Horace Mann Educators Corp.	521		21,794
NMI Holdings, Inc., Class A ^(a)	626		12,908
Palomar Holdings, Inc. ^(a)	97		6,207
ProAssurance Corp.	532		14,300
Safety Insurance Group, Inc.	153		13,900
SiriusPoint Ltd. ^(a)	877		6,560
Stewart Information Services Corp.	338		20,486
Universal Insurance Holdings, Inc.	304		4,101
		$	165,058

Internet — 1.28%
Cars.com, Inc. ^(a)	344		4,964
Cogent Communications Holdings, Inc.	311		20,635
ePlus, Inc. ^(a)	261		14,631
HealthStream, Inc. ^(a)	215		4,283
Perficient, Inc. ^(a)	187		20,587
Shutterstock, Inc.	80		7,446

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Internet (continued)
TechTarget, Inc. ^(a)	92	$	7,478
		$	80,024

Iron & Steel — 0.16%
Allegheny Technologies, Inc. ^(a)	363		9,743

Lodging — 0.09%
Marcus Corp. ^(a)	309		5,469

Machinery — Diversified — 1.92%
Alamo Group, Inc.	96		13,804
Albany International Corp., Class A	230		19,394
Applied Industrial Technologies, Inc.	348		35,726
Ichor Holdings Ltd. ^(a)	146		5,200
Lindsay Corp.	57		8,950
SPX FLOW, Inc.	278		23,969
Tennant Co.	173		13,632
		$	120,675

Media — 0.51%
EW Scripps Co., Class A ^(a)	515		10,707
Gannett Co., Inc. ^(a)	1,029		4,641
Scholastic Corp.	314		12,648
Thryv Holdings, Inc. ^(a)	144		4,049
		$	32,045

Metal Fabrication & Hardware — 1.21%
AZZ, Inc.	262		12,639
Mueller Industries, Inc.	555		30,064
Olympic Steel, Inc.	123		4,730
Standex International Corp.	178		17,786
TimkenSteel Corp. ^(a)	249		5,448
Tredegar Corp.	436		5,228
		$	75,895

Mining — 0.42%
Arconic Corp. ^(a)	334		8,557
Century Aluminum Co. ^(a)	229		6,025
Livent Corp. ^(a)	445		11,601
		$	26,183

Miscellaneous Manufacture — 2.37%
EnPro Industries, Inc.	239		23,358
ESCO Technologies, Inc.	126		8,810
Fabrinet ^(a)	205		21,552
Federal Signal Corp.	488		16,470
Haynes International, Inc.	102		4,345
Hillenbrand, Inc.	488		21,555
John Bean Technologies Corp.	88		10,425
Materion Corp.	256		21,949
Myers Industries, Inc.	334		7,214
Sturm Ruger & Co., Inc.	182		12,671
		$	148,349

Office Furnishings — 0.39%
HNI Corp.	402		14,894
Interface, Inc.	713		9,676
		$	24,570

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Oil & Gas — 3.04%
Callon Petroleum Co. ^(a)	285	$	16,838
Civitas Resources, Inc.	195		11,644
Helmerich & Payne, Inc.	281		12,021
Laredo Petroleum, Inc. ^(a)	71		5,619
Matador Resources Co.	701		37,139
Nabors Industries Ltd. ^(a)	35		5,345
Patterson-UTI Energy, Inc.	607		9,397
PBF Energy, Inc., Class A ^(a)	306		7,457
Ranger Oil Corp., Class A ^(a)	127		4,385
SM Energy Co.	774		30,147
Southwestern Energy Co. ^(a)	6,455		46,282
Talos Energy, Inc. ^(a)	283		4,469
		$	190,743

Oil & Gas Services — 0.53%
Archrock, Inc.	1,414		13,051
Bristow Group, Inc. ^(a)	129		4,783
Oceaneering International, Inc. ^(a)	386		5,852
ProPetro Holding Corp. ^(a)	382		5,321
RPC, Inc. ^(a)	416		4,439
		$	33,446

Packaging & Containers — 0.23%
Matthews International Corp., Class A	211		6,828
O-I Glass, Inc. ^(a)	571		7,526
		$	14,354

Pharmaceuticals — 1.95%
Amphastar Pharmaceuticals, Inc. ^(a)	321		11,524
Corcept Therapeutics, Inc. ^(a)	303		6,823
Cytokinetics, Inc. ^(a)	243		8,945
Eagle Pharmaceuticals, Inc. ^(a)	85		4,207
Enanta Pharmaceuticals, Inc. ^(a)	83		5,908
Harmony Biosciences Holdings, Inc. ^(a)	117		5,692
Owens & Minor, Inc.	225		9,904
Pacira BioSciences, Inc. ^(a)	302		23,049
Phibro Animal Health Corp., Class A	461		9,197
Prestige Consumer Healthcare, Inc. ^(a)	357		18,899
Supernus Pharmaceuticals, Inc. ^(a)	206		6,658
USANA Health Sciences, Inc. ^(a)	142		11,282
		$	122,088

Real Estate — 1.00%
Alexander & Baldwin, Inc.	647		15,004
Marcus & Millichap, Inc.	277		14,592
RE/MAX Holdings, Inc., Class A	200		5,546
Realogy Holdings Corp. ^(a)	844		13,234
St. Joe Co.	240		14,218
		$	62,594

REITs — 11.27%
Acadia Realty Trust	740		16,036
Agree Realty Corp.	430		28,535
American Assets Trust, Inc.	439		16,634
Apollo Commercial Real Estate Finance, Inc.	1,131		15,755
Armada Hoffler Properties, Inc.	783		11,432
ARMOUR Residential REIT, Inc.	735		6,174

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

REITs (continued)
Brandywine Realty Trust	1,321	$	18,679
CareTrust REIT, Inc.	854		16,482
Centerspace	139		13,639
Chatham Lodging Trust ^(a)	756		10,425
Community Healthcare Trust, Inc.	285		12,030
Easterly Government Properties, Inc.	1,046		22,112
Ellington Financial, Inc.	942		16,720
Essential Properties Realty Trust, Inc.	1,213		30,689
Four Corners Property Trust, Inc.	614		16,603
Franklin BSP Realty Trust, Inc.	445		6,221
Franklin Street Properties Corp.	1,743		10,284
GEO Group, Inc. ^(a)	786		5,195
Getty Realty Corp.	254		7,269
Global Net Lease, Inc.	553		8,699
Granite Point Mortgage Trust, Inc.	1,308		14,545
Independence Realty Trust, Inc.	755		19,962
Industrial Logistics Properties Trust	624		14,146
Innovative Industrial Properties, Inc.	61		12,529
Invesco Mortgage Capital, Inc.	2,777		6,332
iStar, Inc.	266		6,227
KKR Real Estate Finance Trust, Inc.	816		16,818
LTC Properties, Inc.	220		8,463
LXP Industrial Trust	1,766		27,726
New York Mortgage Trust, Inc.	2,138		7,804
NexPoint Residential Trust, Inc.	185		16,707
Office Properties Income Trust	295		7,590
PennyMac Mortgage Investment Trust	881		14,880
Ready Capital Corp.	1,063		16,009
Redwood Trust, Inc.	1,709		17,996
Retail Opportunity Investments Corp.	1,331		25,808
RPT Realty	942		12,971
Safehold, Inc.	83		4,602
Saul Centers, Inc.	222		11,699
SITE Centers Corp.	1,260		21,055
Summit Hotel Properties, Inc. ^(a)	1,228		12,231
Tanger Factory Outlet Centers, Inc.	384		6,601
Two Harbors Investment Corp.	1,698		9,390
Uniti Group, Inc.	1,612		22,181
Universal Health Realty Income Trust	181		10,565
Urban Edge Properties	896		17,114
Urstadt Biddle Properties, Inc., Class A	716		13,468
Veris Residential, Inc. ^(a)	788		13,703
Washington Real Estate Investment Trust	682		17,391
Whitestone REIT	790		10,468
		$	706,594

Retail — 4.37%
Abercrombie & Fitch Co., Class A ^(a)	445		14,236
America's Car-Mart, Inc. ^(a)	46		3,706
Asbury Automotive Group, Inc. ^(a)	60		9,612
Big Lots, Inc.	154		5,328
Bloomin' Brands, Inc.	304		6,670
Boot Barn Holdings, Inc. ^(a)	183		17,347
Buckle, Inc.	286		9,449
Caleres, Inc.	238		4,601
Cato Corp., Class A	232		3,401
Chico's FAS, Inc. ^(a)	1,033		4,958
Children's Place, Inc. ^(a)	86		4,240

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Retail (continued)
Chuy's Holdings, Inc. ^(a)	151	$	4,077
Conn's, Inc. ^(a)	412		6,349
El Pollo Loco Holdings, Inc. ^(a)	736		8,552
Genesco, Inc. ^(a)	147		9,351
GMS, Inc. ^(a)	286		14,234
Group 1 Automotive, Inc.	102		17,119
Guess?, Inc.	250		5,462
Haverty Furniture Cos., Inc.	137		3,757
Hibbett, Inc.	97		4,301
Jack in the Box, Inc.	107		9,995
La-Z-Boy, Inc.	192		5,063
MarineMax, Inc. ^(a)	113		4,549
Movado Group, Inc.	247		9,645
ODP Corp. ^(a)	163		7,470
Patrick Industries, Inc.	90		5,427
PC Connection, Inc.	197		10,321
PetMed Express, Inc.	155		3,999
PriceSmart, Inc.	119		9,385
Ruth's Hospitality Group, Inc.	198		4,530
Sally Beauty Holdings, Inc. ^(a)	398		6,221
Shoe Carnival, Inc.	283		8,252
Signet Jewelers Ltd.	150		10,905
Sonic Automotive, Inc., Class A	104		4,421
Vera Bradley, Inc. ^(a)	484		3,712
World Fuel Services Corp.	319		8,626
Zumiez, Inc. ^(a)	117		4,471
		$	273,742

Savings & Loans — 3.24%
Axos Financial, Inc. ^(a)	332		15,402
Banc of California, Inc.	633		12,255
Berkshire Hills Bancorp, Inc.	470		13,616
Brookline Bancorp, Inc.	1,136		17,972
Capitol Federal Financial, Inc.	716		7,790
Investors Bancorp, Inc.	2,142		31,980
Northfield Bancorp, Inc.	679		9,750
Northwest Bancshares, Inc.	1,555		21,008
Pacific Premier Bancorp, Inc.	617		21,811
Provident Financial Services, Inc.	938		21,949
WSFS Financial Corp.	629		29,324
		$	202,857

Semiconductors — 2.19%
Axcelis Technologies, Inc. ^(a)	114		8,610
Cohu, Inc. ^(a)	200		5,920
Diodes, Inc. ^(a)	123		10,700
FormFactor, Inc. ^(a)	223		9,373
Kulicke & Soffa Industries, Inc.	177		9,916
MaxLinear, Inc. ^(a)	198		11,553
Onto Innovation, Inc. ^(a)	266		23,113
Photronics, Inc. ^(a)	601		10,199
Rambus, Inc. ^(a)	754		24,045
SMART Global Holdings, Inc. ^(a)	423		10,926
Ultra Clean Holdings, Inc. ^(a)	162		6,867
Veeco Instruments, Inc. ^(a)	213		5,791
		$	137,013

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Software — 2.79%
Allscripts Healthcare Solutions, Inc. ^(a)	386	$	8,693
Apollo Medical Holdings, Inc. ^(a)	298		14,444
Bottomline Technologies DE, Inc. ^(a)	130		7,368
Computer Programs & Systems, Inc. ^(a)	166		5,719
CSG Systems International, Inc.	380		24,157
Digi International, Inc. ^(a)	530		11,406
Donnelley Financial Solutions, Inc. ^(a)	313		10,410
Ebix, Inc.	129		4,276
ManTech International Corp., Class A	299		25,771
NextGen Healthcare, Inc. ^(a)	646		13,508
PDF Solutions, Inc. ^(a)	177		4,933
Progress Software Corp.	361		16,999
Simulations Plus, Inc.	105		5,353
SPS Commerce, Inc. ^(a)	95		12,464
Xperi Holding Corp.	525		9,093
		$	174,594

Telecommunications — 1.63%
ADTRAN, Inc.	256		4,723
ATN International, Inc.	150		5,982
Consolidated Communications Holdings, Inc. ^(a)	720		4,248
Extreme Networks, Inc. ^(a)	539		6,581
Harmonic, Inc. ^(a)	548		5,091
InterDigital, Inc.	256		16,333
NETGEAR, Inc. ^(a)	259		6,392
Shenandoah Telecommunications Co.	336		7,923
Viavi Solutions, Inc. ^(a)	871		14,006
Vonage Holdings Corp. ^(a)	1,512		30,678
		$	101,957

Textiles — 0.32%
UniFirst Corp.	110		20,271

Transportation — 2.22%
ArcBest Corp.	172		13,846
Atlas Air Worldwide Holdings, Inc. ^(a)	306		26,429
Dorian LPG Ltd.	285		4,130
Forward Air Corp.	280		27,378
Heartland Express, Inc.	426		5,994
Hub Group, Inc., Class A ^(a)	245		18,916
Marten Transport Ltd.	918		16,304
Matson, Inc.	217		26,175
		$	139,172

Trucking & Leasing — 0.10%
Greenbrier Cos., Inc.	124		6,387

Water — 1.38%
American States Water Co.	364		32,403
California Water Service Group	526		31,181
Middlesex Water Co.	217		22,822


	$	86,406
TOTAL COMMON STOCKS	$	6,244,647

See accompanying notes.


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
March 31, 2022 (unaudited)

INVESTMENT COMPANIES — 0.25%	Shares Held		Value
Money Market Fund — 0.25%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(b)	15,535	$	15,535
TOTAL INVESTMENT COMPANIES		$	15,535
Total Investments		$	6,260,182
Other Assets and Liabilities — 0.14%			8,667
Total Net Assets — 100.00%		$	6,268,849


^(a)	Non-income producing security.
^(b)	Current yield shown is as of period end.

Portfolio Summary (unaudited)

Sector		Percent
Financial		36.40	%
Industrial		16.06	%
Consumer, Non-cyclical		15.94	%
Consumer, Cyclical		9.59	%
Technology		6.66	%
Basic Materials		4.86	%
Energy		3.95	%
Communications		3.41	%
Utilities		2.74	%
Money Market Fund		0.25	%
Other Assets and Liabilities		0.14	%
TOTAL NET ASSETS		100.00	%

See accompanying notes.


	Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS — 99.72%	Shares Held		Value

Advertising — 0.03%
Entravision Communications Corp., Class A	30,056	$	192,659

Aerospace & Defense — 0.13%
Barnes Group, Inc.	25,646		1,030,713

Agriculture — 0.23%
Alico, Inc.	3,897		146,371
Andersons, Inc.	7,297		366,747
Turning Point Brands, Inc.	8,337		283,541
Universal Corp.	10,563		613,394
Vector Group Ltd.	28,014		337,289
		$	1,747,342

Apparel — 1.09%
Kontoor Brands, Inc.	32,939		1,362,028
Levi Strauss & Co., Class A	149,451		2,953,152
Oxford Industries, Inc.	8,722		789,341
Steven Madden Ltd.	61,906		2,392,048
Wolverine World Wide, Inc.	41,390		933,758
		$	8,430,327

Auto Manufacturers — 0.04%
REV Group, Inc.	24,038		322,109

Auto Parts & Equipment — 0.86%
Dana, Inc.	57,529		1,010,785
Gentherm, Inc. ^(a)	9,560		698,262
Goodyear Tire & Rubber Co. ^(a)	186,991		2,672,101
Methode Electronics, Inc.	25,016		1,081,942
Shyft Group, Inc.	17,556		633,947
Standard Motor Products, Inc.	13,076		564,099
		$	6,661,136

Banks — 8.34%
1st Source Corp.	11,022		509,768
Ameris Bancorp	70,674		3,101,175
Bancorp, Inc. ^(a)	44,421		1,258,447
Byline Bancorp, Inc.	28,820		768,918
Camden National Corp.	8,406		395,418
Cathay General Bancorp	62,825		2,811,419
City Holding Co.	13,275		1,044,742
Community Trust Bancorp, Inc.	13,601		560,361
Customers Bancorp, Inc. ^(a)	29,257		1,525,460
CVB Financial Corp.	130,685		3,033,199
Eagle Bancorp, Inc.	23,483		1,338,766
Enterprise Financial Services Corp.	27,996		1,324,491
FB Financial Corp.	25,613		1,137,729
First Bancshares, Inc.	16,953		570,638
First Busey Corp.	31,950		809,613
First Financial Bancorp	79,419		1,830,608
First Financial Corp.	13,383		579,216
First Foundation, Inc.	30,444		739,485
First Merchants Corp.	36,943		1,536,829
First of Long Island Corp.	15,944		310,270
German American Bancorp, Inc.	8,236		312,886
Hanmi Financial Corp.	21,651		532,831
Hilltop Holdings, Inc.	115,213		3,387,262
Home BancShares, Inc.	121,669		2,749,719
Hope Bancorp, Inc.	143,595		2,309,008

See accompanying notes.


	Schedule of Investments
	Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Banks (continued)
Horizon Bancorp, Inc.	19,273	$	359,827
Independent Bank Corp.	19,275		424,050
Independent Bank Group, Inc.	27,419		1,951,136
Kearny Financial Corp.	75,458		971,899
Lakeland Bancorp, Inc.	47,561		794,269
Lakeland Financial Corp.	44,283		3,232,659
Merchants Bancorp	12,196		333,926
Meta Financial Group, Inc.	29,459		1,617,888
Metropolitan Bank Holding Corp. ^(a)	8,108		825,151
Midland States Bancorp, Inc.	15,731		453,997
Origin Bancorp, Inc.	9,902		418,756
Preferred Bank	10,790		799,431
Premier Financial Corp.	18,431		559,012
QCR Holdings, Inc.	12,622		714,279
Sandy Spring Bancorp, Inc.	27,568		1,238,355
ServisFirst Bancshares, Inc.	29,591		2,819,726
Simmons First National Corp., Class A	76,521		2,006,381
Stock Yards Bancorp, Inc.	11,909		629,986
Tompkins Financial Corp.	6,417		502,259
TriCo Bancshares	18,412		737,032
Triumph Bancorp, Inc. ^(a)	22,319		2,098,432
UMB Financial Corp.	44,963		4,368,605
Veritex Holdings, Inc.	36,743		1,402,480
Washington Trust Bancorp, Inc.	11,199		587,948
		$	64,325,742

Beverages — 0.16%
Coca-Cola Consolidated, Inc.	1,798		893,337
MGP Ingredients, Inc.	3,836		328,323
		$	1,221,660

Biotechnology — 2.58%
Agenus, Inc. ^(a)	223,242		549,175
AnaptysBio, Inc. ^(a)	12,262		303,362
ANI Pharmaceuticals, Inc. ^(a)	3,890		109,348
Avid Bioservices, Inc. ^(a)	31,516		641,981
Cara Therapeutics, Inc. ^(a)	84,115		1,021,997
Cardiff Oncology, Inc. ^(a)	50,213		124,528
Cassava Sciences, Inc. ^(a),(b)	89,875		3,337,958
Celldex Therapeutics, Inc. ^(a)	29,820		1,015,669
Clearside Biomedical, Inc. ^(a)	38,635		88,474
Curis, Inc. ^(a)	87,511		208,276
Dynavax Technologies Corp. ^(a)	109,530		1,187,305
EyePoint Pharmaceuticals, Inc. ^(a)	7,413		90,068
Harvard Bioscience, Inc. ^(a)	18,918		117,481
Ideaya Biosciences, Inc. ^(a)	14,647		163,900
ImmunoGen, Inc. ^(a)	112,106		533,625
Innoviva, Inc. ^(a)	75,984		1,470,290
Intercept Pharmaceuticals, Inc. ^(a),(b)	60,235		980,024
Intra-Cellular Therapies, Inc. ^(a)	31,138		1,905,334
Lexicon Pharmaceuticals, Inc. ^(a)	35,482		74,157
Ligand Pharmaceuticals, Inc. ^(a)	12,176		1,369,678
Lineage Cell Therapeutics, Inc. ^(a)	45,159		69,545
Myriad Genetics, Inc. ^(a)	38,897		980,204
Oncternal Therapeutics, Inc. ^(a)	31,956		44,419
Organogenesis Holdings, Inc. ^(a)	53,069		404,386
Prothena Corp. PLC ^(a)	19,738		721,819
Puma Biotechnology, Inc. ^(a)	33,483		96,431

See accompanying notes.


	Schedule of Investments
	Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Biotechnology (continued)
Radius Health, Inc. ^(a)	35,244	$	311,205
Selecta Biosciences, Inc. ^(a)	37,881		46,594
Surface Oncology, Inc. ^(a)	38,952		114,519
Sutro Biopharma, Inc. ^(a)	21,406		175,957
TransMedics Group, Inc. ^(a)	14,014		377,537
Verastem, Inc. ^(a)	148,363		209,192
Vericel Corp. ^(a)	24,905		951,869
VistaGen Therapeutics, Inc. ^(a)	78,879		97,810
		$	19,894,117

Building Materials — 0.85%
Apogee Enterprises, Inc.	16,646		790,019
Boise Cascade Co.	36,403		2,528,917
Griffon Corp.	21,866		437,976
UFP Industries, Inc.	36,526		2,818,346
		$	6,575,258

Chemicals — 2.39%
AdvanSix, Inc.	19,122		976,943
Balchem Corp.	17,418		2,381,041
Cabot Corp.	39,327		2,690,360
HB Fuller Co.	42,654		2,818,150
Ingevity Corp. ^(a)	24,825		1,590,538
Koppers Holdings, Inc.	10,197		280,621
Minerals Technologies, Inc.	18,303		1,210,743
NewMarket Corp.	7,596		2,463,991
Sensient Technologies Corp.	31,748		2,665,245
Trinseo PLC	28,396		1,360,736
		$	18,438,368

Coal — 0.41%
Alpha Metallurgical Resources, Inc. ^(a)	12,553		1,656,494
CONSOL Energy, Inc. ^(a)	22,533		847,917
SunCoke Energy, Inc.	70,323		626,578
		$	3,130,989

Commercial Services — 5.23%
ABM Industries, Inc.	72,785		3,351,021
AMN Healthcare Services, Inc. ^(a)	38,428		4,009,193
Brink's Co.	35,980		2,446,640
Carriage Services, Inc.	11,037		588,603
Cass Information Systems, Inc.	5,773		213,081
CBIZ, Inc. ^(a)	28,385		1,191,319
CorVel Corp. ^(a)	3,615		608,911
CRA International, Inc.	3,561		300,050
Deluxe Corp.	24,017		726,274
EVERTEC, Inc.	46,982		1,922,973
Franklin Covey Co. ^(a)	5,907		267,115
Graham Holdings Co., Class B	3,106		1,899,226
H&R Block, Inc.	188,864		4,918,019
Hackett Group, Inc.	16,377		377,654
Herc Holdings, Inc.	12,648		2,113,354
ICF International, Inc.	10,618		999,579
Information Services Group, Inc.	34,134		232,453
Insperity, Inc.	25,289		2,539,521
John Wiley & Sons, Inc., Class A	25,333		1,343,409
Kforce, Inc.	13,934		1,030,698
Korn Ferry	32,412		2,104,835

See accompanying notes.


	Schedule of Investments
	Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Commercial Services (continued)
Medifast, Inc.	6,582	$	1,124,074
Monro, Inc.	10,483		464,816
Rent-A-Center, Inc.	34,991		881,423
Resources Connection, Inc.	15,451		264,830
Stride, Inc. ^(a)	24,995		908,068
Transcat, Inc. ^(a)	2,465		200,010
Triton International Ltd.	47,045		3,301,618
		$	40,328,767

Computers — 1.19%
ExlService Holdings, Inc. ^(a)	25,829		3,700,521
Insight Enterprises, Inc. ^(a)	40,722		4,370,285
Rimini Street, Inc. ^(a)	29,858		173,176
Super Micro Computer, Inc. ^(a)	23,645		900,165
		$	9,144,147

Distribution/Wholesale — 1.13%
A-Mark Precious Metals, Inc.	4,364		337,512
Avient Corp.	43,871		2,105,808
G-III Apparel Group Ltd. ^(a)	22,303		603,296
Leslie's, Inc. ^(a)	123,803		2,396,826
Resideo Technologies, Inc. ^(a)	70,006		1,668,243
ScanSource, Inc. ^(a)	7,442		258,907
Titan Machinery, Inc. ^(a)	14,630		413,444
Veritiv Corp. ^(a)	6,857		916,027
		$	8,700,063

Diversified Financial Services — 6.24%
Alliance Data Systems Corp.	55,291		3,104,590
Atlanticus Holdings Corp. ^(a)	3,983		206,280
B Riley Financial, Inc.	48,602		3,400,196
Brightsphere Investment Group, Inc.	134,186		3,254,010
Columbia Financial, Inc. ^(a)	43,715		940,310
Cowen, Inc., Class A	79,403		2,151,821
Diamond Hill Investment Group, Inc.	2,560		479,488
Encore Capital Group, Inc. ^(a)	44,159		2,770,094
Enova International, Inc. ^(a)	36,605		1,389,892
Federated Hermes, Inc.	105,101		3,579,740
Houlihan Lokey, Inc.	60,866		5,344,035
Moelis & Co., Class A	79,918		3,752,150
Mr Cooper Group, Inc. ^(a)	136,081		6,214,819
Navient Corp.	284,516		4,848,153
Piper Sandler Cos.	14,141		1,856,006
Regional Management Corp.	8,374		406,725
StepStone Group, Inc., Class A	47,403		1,567,143
Victory Capital Holdings, Inc., Class A	12,495		360,731
Virtus Investment Partners, Inc.	7,423		1,781,446
World Acceptance Corp. ^(a)	3,854		739,351
		$	48,146,980

Electric — 1.01%
Avista Corp.	50,899		2,298,090
Otter Tail Corp.	18,084		1,130,250
Portland General Electric Co.	71,271		3,930,596
Unitil Corp.	8,720		434,953
		$	7,793,889

See accompanying notes.


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Electrical Components & Equipment — 0.48%
Encore Wire Corp.	13,441	$	1,533,215
Energizer Holdings, Inc.	58,437		1,797,522
Insteel Industries, Inc.	10,187		376,817
		$	3,707,554

Electronics — 2.71%
Advanced Energy Industries, Inc.	23,302		2,005,836
Atkore, Inc. ^(a)	31,657		3,116,315
Avnet, Inc.	118,590		4,813,568
Badger Meter, Inc.	14,752		1,470,922
Benchmark Electronics, Inc.	26,072		652,843
Comtech Telecommunications Corp.	14,722		230,988
CTS Corp.	20,767		733,906
Fluidigm Corp. ^(a),(b)	45,159		162,121
Kimball Electronics, Inc. ^(a)	6,277		125,477
Napco Security Technologies, Inc. ^(a)	5,986		122,833
NVE Corp.	3,120		169,946
OSI Systems, Inc. ^(a)	20,021		1,704,188
Sanmina Corp. ^(a)	47,564		1,922,537
Vicor Corp. ^(a)	12,546		885,120
Vishay Intertechnology, Inc.	139,969		2,743,392
		$	20,859,992

Engineering & Construction — 1.11%
Arcosa, Inc.	45,994		2,633,157
Comfort Systems USA, Inc.	20,214		1,799,248
Granite Construction, Inc.	33,817		1,109,198
MYR Group, Inc. ^(a)	12,134		1,141,081
NV5 Global, Inc. ^(a)	7,220		962,426
Primoris Services Corp.	37,654		896,918
		$	8,542,028

Entertainment — 0.24%
RCI Hospitality Holdings, Inc.	2,271		139,575
Warner Music Group Corp., Class A	45,435		1,719,715
		$	1,859,290

Environmental Control — 0.72%
Casella Waste Systems, Inc., Class A ^(a)	18,574		1,628,011
Centrus Energy Corp., Class A ^(a)	3,517		118,523
Energy Recovery, Inc. ^(a)	31,739		639,223
Evoqua Water Technologies Corp. ^(a)	67,251		3,159,452
		$	5,545,209

Food — 1.66%
B&G Foods, Inc.	55,176		1,488,648
Hain Celestial Group, Inc. ^(a)	43,886		1,509,678
Hostess Brands, Inc. ^(a)	72,561		1,591,988
Ingles Markets, Inc., Class A	4,932		439,195
John B Sanfilippo & Son, Inc.	3,650		304,556
Seaboard Corp.	48		201,864
Simply Good Foods Co. ^(a)	30,182		1,145,407
SpartanNash Co.	18,660		615,593
Sprouts Farmers Market, Inc. ^(a)	153,144		4,897,545
United Natural Foods, Inc. ^(a)	15,422		637,700
		$	12,832,174

See accompanying notes.


	Schedule of Investments
	Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Food Service — 0.25%
Healthcare Services Group, Inc.	102,295	$	1,899,618

Forest Products & Paper — 0.10%
Neenah, Inc.	10,377		411,552
Schweitzer-Mauduit International, Inc.	14,389		395,697
		$	807,249

Gas — 1.47%
Chesapeake Utilities Corp.	4,905		675,713
National Fuel Gas Co.	40,868		2,807,631
South Jersey Industries, Inc.	110,998		3,834,981
Southwest Gas Holdings, Inc.	50,858		3,981,673
		$	11,299,998

Hand/Machine Tools — 0.25%
Franklin Electric Co., Inc.	23,667		1,965,308

Healthcare — Products — 4.99%
Accuray, Inc. ^(a)	40,365		133,608
AngioDynamics, Inc. ^(a)	22,552		485,770
AtriCure, Inc. ^(a)	26,436		1,736,052
Atrion Corp.	864		616,032
Avanos Medical, Inc. ^(a)	43,650		1,462,275
Axogen, Inc. ^(a)	11,132		88,388
Axonics, Inc. ^(a)	39,621		2,480,275
Bionano Genomics, Inc. ^(a),(b)	584,308		1,507,515
Castle Biosciences, Inc. ^(a)	10,966		491,935
Co.-Diagnostics, Inc. ^(a)	49,652		306,849
CONMED Corp.	27,664		4,109,487
Cutera, Inc. ^(a)	19,471		1,343,499
Eargo, Inc. ^(a)	156,908		830,043
ICU Medical, Inc. ^(a)	9,919		2,208,366
Inogen, Inc. ^(a)	12,816		415,495
Integer Holdings Corp. ^(a)	14,929		1,202,830
Invacare Corp. ^(a)	30,961		43,655
iRadimed Corp.	2,720		121,965
Lantheus Holdings, Inc. ^(a)	42,285		2,338,783
LeMaitre Vascular, Inc.	15,212		706,902
Meridian Bioscience, Inc. ^(a)	22,992		596,872
Merit Medical Systems, Inc. ^(a)	27,500		1,829,300
Natus Medical, Inc. ^(a)	12,150		319,302
Neogen Corp. ^(a)	43,772		1,349,928
NuVasive, Inc. ^(a)	72,000		4,082,400
Orthofix Medical, Inc. ^(a)	9,936		324,907
OrthoPediatrics Corp. ^(a)	7,222		389,916
Patterson Cos., Inc.	114,462		3,705,135
Quanterix Corp. ^(a)	13,449		392,576
SI-BONE, Inc. ^(a)	27,030		610,878
Sientra, Inc. ^(a)	50,016		111,036
Silk Road Medical, Inc. ^(a)	16,068		663,448
Surmodics, Inc. ^(a)	3,648		165,364
T2 Biosystems, Inc. ^(a),(b)	158,992		83,328
Treace Medical Concepts, Inc. ^(a)	11,573		218,845
Varex Imaging Corp. ^(a)	32,866		699,717
ViewRay, Inc. ^(a)	71,624		280,766
		$	38,453,442

Healthcare — Services — 1.70%
Agiliti, Inc. ^(a)	16,041		338,465

See accompanying notes.


	Schedule of Investments
	Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Healthcare — Services (continued)
ATI Physical Therapy, Inc. ^(a)	85,164	$	160,108
Aveanna Healthcare Holdings, Inc. ^(a)	44,658		152,284
Brookdale Senior Living, Inc. ^(a)	170,989		1,205,472
Community Health Systems, Inc. ^(a)	92,386		1,096,622
Ensign Group, Inc.	29,250		2,632,792
Innovage Holding Corp. ^(a)	41,328		265,326
Inotiv, Inc. ^(a)	3,270		85,609
Joint Corp. ^(a)	10,761		380,832
MEDNAX, Inc. ^(a)	45,488		1,068,058
ModivCare, Inc. ^(a)	5,735		661,762
National HealthCare Corp.	4,699		330,011
Neuronetics, Inc. ^(a)	21,167		64,136
OPKO Health, Inc. ^(a)	246,530		848,063
Pennant Group, Inc. ^(a)	5,759		107,290
RadNet, Inc. ^(a)	22,537		504,153
Surgery Partners, Inc. ^(a)	29,156		1,605,038
Tivity Health, Inc. ^(a)	37,087		1,193,089
U.S. Physical Therapy, Inc.	4,488		446,331
		$	13,145,441

Home Builders — 1.00%
Century Communities, Inc.	25,873		1,386,016
Hovnanian Enterprises, Inc., Class A ^(a)	3,608		213,233
LCI Industries	9,790		1,016,300
Skyline Champion Corp. ^(a)	28,602		1,569,678
Tri Pointe Homes, Inc. ^(a)	90,511		1,817,461
Winnebago Industries, Inc.	31,941		1,725,772
		$	7,728,460

Home Furnishings — 0.85%
Ethan Allen Interiors, Inc.	18,839		491,133
Lovesac Co. ^(a)	12,055		651,693
Sonos, Inc. ^(a)	173,767		4,903,705
Universal Electronics, Inc. ^(a)	4,275		133,551
Vizio Holding Corp., Class A ^(a)	41,495		368,890
		$	6,548,972

Household Products — 0.24%
Edgewell Personal Care Co.	33,384		1,224,191
Inter Parfums, Inc.	7,161		630,526
		$	1,854,717

Household Products/Wares — 0.37%
ACCO Brands Corp.	19,148		153,184
Central Garden & Pet Co., Class A ^(a)	17,226		702,476
Quanex Building Products Corp.	20,563		431,617
Spectrum Brands Holdings, Inc.	17,583		1,559,964
		$	2,847,241

Insurance — 1.84%
Enstar Group Ltd. ^(a)	11,972		3,126,488
Mercury General Corp.	60,990		3,354,450
Radian Group, Inc.	246,741		5,480,118
Stewart Information Services Corp.	37,325		2,262,268
		$	14,223,324

See accompanying notes.

100


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Internet — 1.94%
Cargurus, Inc. ^(a)	92,021	$	3,907,212
ChannelAdvisor Corp. ^(a)	16,701		276,736
ePlus, Inc. ^(a)	13,688		767,349
HealthStream, Inc. ^(a)	13,708		273,063
Perficient, Inc. ^(a)	46,982		5,172,248
Revolve Group, Inc. ^(a)	37,533		2,015,147
Shutterstock, Inc.	27,699		2,578,223
		$	14,989,978

Investment Companies — 0.47%
Golub Capital BDC, Inc.	238,723		3,630,977

Iron & Steel — 0.47%
Commercial Metals Co.	87,879		3,657,524

Leisure Time — 0.61%
Acushnet Holdings Corp.	20,136		810,675
Camping World Holdings, Inc., Class A	59,514		1,663,416
Clarus Corp.	15,353		349,741
OneWater Marine, Inc., Class A	3,572		123,056
Vista Outdoor, Inc. ^(a)	49,060		1,750,952
		$	4,697,840

Lodging — 0.01%
Full House Resorts, Inc. ^(a)	9,474		91,045

Machinery — Construction & Mining — 0.29%
Terex Corp.	63,759		2,273,646

Machinery — Diversified — 1.78%
Albany International Corp., Class A	15,147		1,277,195
Altra Industrial Motion Corp.	26,072		1,014,983
Applied Industrial Technologies, Inc.	16,531		1,697,072
Cactus, Inc., Class A	32,704		1,855,625
Ichor Holdings Ltd. ^(a)	22,243		792,296
Kadant, Inc.	2,985		579,657
Lindsay Corp.	6,760		1,061,388
Mueller Water Products, Inc., Class A	133,394		1,723,450
Tennant Co.	10,502		827,558
Watts Water Technologies, Inc., Class A	20,467		2,856,988
		$	13,686,212

Media — 0.74%
AMC Networks, Inc., Class A ^(a)	20,390		828,446
EW Scripps Co., Class A ^(a)	17,838		370,852
Gray Television, Inc.	38,427		848,084
Scholastic Corp.	10,876		438,085
Sinclair Broadcast Group, Inc., Class A	24,329		681,698
TEGNA, Inc.	85,832		1,922,637
WideOpenWest, Inc. ^(a)	34,391		599,779
		$	5,689,581

Metal Fabrication & Hardware — 0.69%
AZZ, Inc.	11,895		573,815
Helios Technologies, Inc.	10,460		839,415
Mueller Industries, Inc.	25,316		1,371,368
Standex International Corp.	9,751		974,320
Worthington Industries, Inc.	30,259		1,555,615
		$	5,314,533

See accompanying notes.

101


	Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Mining — 0.10%
Kaiser Aluminum Corp.	8,025	$	755,634

Miscellaneous Manufacture — 1.27%
American Outdoor Brands, Inc. ^(a)	8,489		111,461
EnPro Industries, Inc.	10,152		992,155
Federal Signal Corp.	26,996		911,115
Hillenbrand, Inc.	55,538		2,453,113
John Bean Technologies Corp.	19,165		2,270,478
Myers Industries, Inc.	17,784		384,134
Smith & Wesson Brands, Inc.	110,239		1,667,916
Sturm Ruger & Co., Inc.	14,030		976,769
		$	9,767,141

Office & Business Equipment — 0.73%
Xerox Holdings Corp.	278,126		5,609,801

Office Furnishings — 0.12%
HNI Corp.	17,149		635,371
Interface, Inc.	19,099		259,173
		$	894,544

Oil & Gas — 4.00%
Brigham Minerals, Inc., Class A	25,011		639,031
California Resources Corp.	62,900		2,813,517
Callon Petroleum Co. ^(a)	76,805		4,537,639
Civitas Resources, Inc.	45,370		2,709,043
Comstock Resources, Inc. ^(a)	150,692		1,966,531
Falcon Minerals Corp.	43,798		295,198
Matador Resources Co.	94,214		4,991,458
Oasis Petroleum, Inc.	22,866		3,345,296
PDC Energy, Inc.	58,831		4,275,837
SilverBow Resources, Inc. ^(a)	7,741		247,712
Transocean Ltd. ^(a)	1,100,290		5,028,325
		$	30,849,587

Oil & Gas Services — 0.93%
Archrock, Inc.	81,595		753,122
ChampionX Corp. ^(a)	102,052		2,498,233
Core Laboratories NV	56,725		1,794,212
Oceaneering International, Inc. ^(a)	52,428		794,808
Solaris Oilfield Infrastructure, Inc., Class A	19,134		216,023
TETRA Technologies, Inc. ^(a)	92,735		381,141
Weatherford International PLC ^(a)	21,149		704,261
		$	7,141,800

Packaging & Containers — 0.65%
Greif, Inc., Class A	17,827		1,159,825
Matthews International Corp., Class A	8,858		286,645
Silgan Holdings, Inc.	76,598		3,541,125
		$	4,987,595

Pharmaceuticals — 5.02%
Aclaris Therapeutics, Inc. ^(a)	25,318		436,482
Agios Pharmaceuticals, Inc. ^(a)	65,008		1,892,383
Akebia Therapeutics, Inc. ^(a)	143,710		103,169
Alkermes PLC ^(a)	154,691		4,069,920
Amneal Pharmaceuticals, Inc. ^(a)	68,507		285,674
Amphastar Pharmaceuticals, Inc. ^(a)	23,549		845,409

See accompanying notes.

102


	Schedule of Investments
	Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Pharmaceuticals (continued)
Anika Therapeutics, Inc. ^(a)	8,469	$	212,657
Antares Pharma, Inc. ^(a)	68,546		281,039
Catalyst Pharmaceuticals, Inc. ^(a)	78,804		653,285
Clovis Oncology, Inc. ^(a),(b)	269,623		544,638
Coherus Biosciences, Inc. ^(a)	49,964		645,035
Collegium Pharmaceutical, Inc. ^(a)	19,797		403,067
Cytokinetics, Inc. ^(a)	55,312		2,036,035
Eagle Pharmaceuticals, Inc. ^(a)	8,146		403,146
Endo International PLC ^(a)	281,350		649,918
Harrow Health, Inc. ^(a)	10,469		71,399
Heat Biologics, Inc. ^(a)	21,392		65,460
Heska Corp. ^(a)	4,267		590,041
Ironwood Pharmaceuticals, Inc. ^(a)	228,919		2,879,801
Jaguar Health, Inc. ^(a),(b)	108,500		76,872
Jounce Therapeutics, Inc. ^(a)	18,373		124,753
MannKind Corp. ^(a)	188,959		695,369
Option Care Health, Inc. ^(a)	163,901		4,681,013
Owens & Minor, Inc.	86,290		3,798,486
Pacira BioSciences, Inc. ^(a)	39,616		3,023,493
Paratek Pharmaceuticals, Inc. ^(a)	33,301		98,904
PetIQ, Inc. ^(a)	48,295		1,178,398
Phibro Animal Health Corp., Class A	11,650		232,417
Premier, Inc., Class A	105,014		3,737,448
Prestige Consumer Healthcare, Inc. ^(a)	31,088		1,645,799
SIGA Technologies, Inc. ^(a)	25,069		177,739
Supernus Pharmaceuticals, Inc. ^(a)	43,787		1,415,196
USANA Health Sciences, Inc. ^(a)	4,986		396,138
Vanda Pharmaceuticals, Inc. ^(a)	33,026		373,524
		$	38,724,107

Pipelines — 1.00%
Antero Midstream Corp.	405,294		4,405,546
Equitrans Midstream Corp.	357,482		3,017,148
Kinetik Holdings, Inc.	4,308		280,063
		$	7,702,757

Real Estate — 0.58%
Alexander & Baldwin, Inc.	36,420		844,580
Douglas Elliman, Inc.	15,846		115,676
Kennedy-Wilson Holdings, Inc.	69,646		1,698,666
Newmark Group, Inc., Class A	65,705		1,046,023
RE/MAX Holdings, Inc., Class A	19,546		542,010
RMR Group, Inc., Class A	7,957		247,463
		$	4,494,418

REITs — 6.85%
Ares Commercial Real Estate Corp.	77,529		1,203,250
Brandywine Realty Trust	293,849		4,155,025
Broadstone Net Lease, Inc.	159,400		3,471,732
CareTrust REIT, Inc.	99,266		1,915,834
Corporate Office Properties Trust	137,688		3,929,616
CTO Realty Growth, Inc.	4,970		329,610
Essential Properties Realty Trust, Inc.	108,076		2,734,323
GEO Group, Inc. ^(a)	236,522		1,563,410
Getty Realty Corp.	31,213		893,316
Gladstone Commercial Corp.	32,831		722,939
Healthcare Realty Trust, Inc.	188,424		5,177,892
Industrial Logistics Properties Trust	49,565		1,123,639

See accompanying notes.

103


	Schedule of Investments
	Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

REITs (continued)
KKR Real Estate Finance Trust, Inc.	134,813	$	2,778,496
LTC Properties, Inc.	59,269		2,280,078
National Health Investors, Inc.	57,951		3,419,689
National Storage Affiliates Trust	106,133		6,660,907
NexPoint Residential Trust, Inc.	15,161		1,369,190
One Liberty Properties, Inc.	8,851		272,522
PotlatchDeltic Corp.	59,459		3,135,273
Preferred Apartment Communities, Inc.	38,946		971,313
Retail Value, Inc.	46,597		142,587
Saul Centers, Inc.	3,955		208,428
Tanger Factory Outlet Centers, Inc.	87,959		1,512,015
UMH Properties, Inc.	26,635		654,955
Urban Edge Properties	96,835		1,849,548
Urstadt Biddle Properties, Inc., Class A	16,745		314,973
		$	52,790,560

Retail — 7.75%
Abercrombie & Fitch Co., Class A ^(a)	88,423		2,828,652
Academy Sports & Outdoors, Inc.	140,339		5,529,357
Asbury Automotive Group, Inc. ^(a)	11,692		1,873,058
Bassett Furniture Industries, Inc.	5,016		83,065
Big 5 Sporting Goods Corp. ^(b)	48,730		835,720
BlueLinx Holdings, Inc. ^(a)	11,659		838,049
Boot Barn Holdings, Inc. ^(a)	23,085		2,188,227
Buckle, Inc.	35,199		1,162,975
Caleres, Inc.	24,656		476,600
Cato Corp., Class A	6,767		99,204
Citi Trends, Inc. ^(a)	10,486		321,134
Dillard's, Inc., Class A	15,876		4,260,960
Duluth Holdings, Inc., Class B ^(a)	14,941		182,728
Franchise Group, Inc.	13,682		566,845
Genesco, Inc. ^(a)	5,351		340,377
GMS, Inc. ^(a)	26,492		1,318,507
Group 1 Automotive, Inc.	8,718		1,463,142
Haverty Furniture Cos., Inc.	17,165		470,664
Hibbett, Inc.	24,918		1,104,864
Jack in the Box, Inc.	33,817		3,158,846
La-Z-Boy, Inc.	32,129		847,242
MarineMax, Inc. ^(a)	18,718		753,587
Movado Group, Inc.	7,645		298,537
MSC Industrial Direct Co., Inc., Class A	69,941		5,959,673
Murphy USA, Inc.	16,839		3,367,126
National Vision Holdings, Inc. ^(a)	57,605		2,509,850
Nu Skin Enterprises, Inc., Class A	30,046		1,438,602
OptimizeRx Corp. ^(a)	8,001		301,718
Papa John's International, Inc.	33,526		3,529,617
Patrick Industries, Inc.	14,085		849,325
PC Connection, Inc.	7,165		375,374
PriceSmart, Inc.	9,080		716,140
Qurate Retail, Inc., Series A	366,909		1,746,487
Rush Enterprises, Inc., Class A	15,372		782,589
Sally Beauty Holdings, Inc. ^(a)	67,222		1,050,680
Shoe Carnival, Inc.	16,388		477,874
Signet Jewelers Ltd.	33,439		2,431,015
Sonic Automotive, Inc., Class A	17,735		753,915
Tilly's, Inc., Class A	23,239		217,517
Winmark Corp.	795		174,900

See accompanying notes.

104


	Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Retail (continued)
World Fuel Services Corp.	75,367	$	2,037,924
		$	59,722,666

Savings & Loans — 1.10%
Axos Financial, Inc. ^(a)	38,626		1,791,860
Flushing Financial Corp.	26,039		581,972
Hingham Institution For Savings The	1,994		684,341
Northfield Bancorp, Inc.	49,320		708,235
OceanFirst Financial Corp.	41,918		842,552
Pacific Premier Bancorp, Inc.	59,185		2,092,190
Provident Financial Services, Inc.	53,669		1,255,854
Waterstone Financial, Inc.	26,743		517,210
		$	8,474,214

Semiconductors — 1.81%
Alpha & Omega Semiconductor Ltd. ^(a)	18,313		1,000,805
Diodes, Inc. ^(a)	27,126		2,359,691
EMCORE Corp. ^(a)	28,091		103,937
MACOM Technology Solutions Holdings, Inc. ^(a)	38,534		2,307,031
Onto Innovation, Inc. ^(a)	25,388		2,205,963
Semtech Corp. ^(a)	37,691		2,613,494
SMART Global Holdings, Inc. ^(a)	93,763		2,421,898
Veeco Instruments, Inc. ^(a)	34,015		924,868
		$	13,937,687

Software — 3.38%
Altair Engineering, Inc., Class A ^(a)	32,265		2,077,866
American Software, Inc., Class A	13,535		282,069
Blackbaud, Inc. ^(a)	35,556		2,128,738
Cerence, Inc. ^(a)	42,931		1,549,809
CommVault Systems, Inc. ^(a)	39,150		2,597,602
Computer Programs & Systems, Inc. ^(a)	10,597		365,067
Convey Health Solutions Holdings, Inc. ^(a)	12,238		80,037
CSG Systems International, Inc.	29,294		1,862,220
Donnelley Financial Solutions, Inc. ^(a)	14,801		492,281
Ebix, Inc.	17,524		580,921
Evolent Health, Inc., Class A ^(a)	52,409		1,692,811
Health Catalyst, Inc. ^(a)	45,073		1,177,757
Loyalty Ventures, Inc. ^(a)	22,139		365,958
NextGen Healthcare, Inc. ^(a)	34,762		726,873
Phreesia, Inc. ^(a)	32,983		869,432
Privia Health Group, Inc. ^(a)	33,234		888,345
Progress Software Corp.	32,043		1,508,905
Sciplay Corp., Class A ^(a)	33,308		430,339
Signify Health, Inc., Class A ^(a)	115,528		2,096,833
Simulations Plus, Inc.	12,298		626,952
SPS Commerce, Inc. ^(a)	19,552		2,565,222
Xperi Holding Corp.	59,695		1,033,917
Zedge, Inc., Class B ^(a)	13,819		84,158
		$	26,084,112

Telecommunications — 2.55%
A10 Networks, Inc.	50,664		706,763
ADTRAN, Inc.	33,182		612,208
Aviat Networks, Inc. ^(a)	13,283		408,718
Calix, Inc. ^(a)	38,056		1,632,983
Cambium Networks Corp. ^(a)	17,110		404,481
Casa Systems, Inc. ^(a)	25,629		115,843

See accompanying notes.

105


	Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Telecommunications (continued)
Clearfield, Inc. ^(a)	6,410	$	418,060
CommScope Holding Co., Inc. ^(a)	266,937		2,103,464
Consolidated Communications Holdings, Inc. ^(a)	36,286		214,087
Extreme Networks, Inc. ^(a)	80,143		978,546
IDT Corp., Class B ^(a)	14,280		486,805
InterDigital, Inc.	28,636		1,826,977
Ribbon Communications, Inc. ^(a)	45,737		141,327
Switch, Inc., Class A	176,689		5,445,555
Telephone & Data Systems, Inc.	112,141		2,117,222
Viasat, Inc. ^(a)	41,330		2,016,904
		$	19,629,943

Toys, Games & Hobbies — 0.07%
Funko, Inc., Class A ^(a)	31,851		549,430

Transportation — 2.20%
ArcBest Corp.	20,261		1,631,010
Atlas Air Worldwide Holdings, Inc. ^(a)	43,618		3,767,287
Daseke, Inc. ^(a)	34,180		344,193
Dorian LPG Ltd.	35,675		516,931
Forward Air Corp.	18,028		1,762,778
International Seaways, Inc.	19,895		358,906
Matson, Inc.	30,486		3,677,221
Pangaea Logistics Solutions Ltd.	27,984		155,591
Ryder System, Inc.	60,226		4,777,728
		$	16,991,645

Water — 0.72%
American States Water Co.	23,744		2,113,691
California Water Service Group	24,497		1,452,182
Middlesex Water Co.	11,903		1,251,839
SJW Group	10,280		715,282
		$	5,532,994
TOTAL COMMON STOCKS		$	768,876,254


INVESTMENT COMPANIES — 1.20%		Shares Held		Value

Money Market Funds — 1.20%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(a),(c),(d),(e)}		5,962,617	$	5,962,617
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(e)		3,288,179		3,288,179
TOTAL INVESTMENT COMPANIES		$		9,250,796
Total Investments		$		778,127,050
Other Assets and Liabilities — (0.92)%				(7,083,452	)

Total Net Assets — 100.00%		$		771,043,598

^(a)	Non-income producing security.
^(b)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $5,539,426 or
	0.72% of net assets.
^(c)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of
	these securities totaled $5,962,617 or 0.77% of net assets.
^(d)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate
	as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(e)	Current yield shown is as of period end.

See accompanying notes.

106


			Schedule of Investments
			Principal U.S. Small-Cap Multi-Factor ETF
			March 31, 2022 (unaudited)

Portfolio Summary (unaudited)
Sector					Percent
Financial					25.43	%
Consumer, Non-cyclical					22.19	%
Consumer, Cyclical					14.02	%
Industrial					13.13	%
Technology					7.11	%
Energy					6.33	%
Communications					5.25	%
Utilities					3.19	%
Basic Materials					3.07	%
Money Market Funds					1.20	%
Other Assets and Liabilities					(0.92	)%
TOTAL NET ASSETS					100.00	%

			June 30, 2021		Purchases		Sales		March 31, 2022
Affiliated Securities			Value		Cost		Proceeds		Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	16,551,960	$	148,422,350	$	159,011,693	$	5,962,617
		$	16,551,960	$	148,422,350	$	159,011,693	$	5,962,617

							Realized Gain
					Realized		from		Change in
					Gain/(Loss) on		Capital Gain		Unrealized
			Income ^(a)		Investments		Distributions		Gain/(Loss)
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$	— $		—	$	—
		$	—	$	— $		—	$	—

^(a)Amount excludes earnings from securities lending collateral.

See accompanying notes.

107


	Schedule of Investments
	Principal Value ETF
	March 31, 2022 (unaudited)

COMMON STOCKS — 99.70%		Shares Held		Value

Aerospace & Defense — 2.67%
Curtiss-Wright Corp.		2,932	$	440,269
General Dynamics Corp.		8,101		1,953,799
L3Harris Technologies, Inc.		6,431		1,597,911
Lockheed Martin Corp.		5,820		2,568,948
			$	6,560,927

Banks — 3.81%
Citigroup, Inc.		48,309		2,579,700
Popular, Inc.		19,678		1,608,480
Prosperity Bancshares, Inc.		31,307		2,172,080
Synovus Financial Corp.		44,359		2,173,591
Western Alliance Bancorp		10,064		833,500
			$	9,367,351

Beverages — 0.90%
Brown-Forman Corp., Class A		35,346		2,217,608

Biotechnology — 1.33%
Gilead Sciences, Inc.		55,231		3,283,483

Building Materials — 0.91%
Eagle Materials, Inc.		2,788		357,868
Masco Corp.		18,183		927,333
Owens Corning		10,451		956,266
			$	2,241,467

Chemicals — 4.64%
Celanese Corp.		9,838		1,405,555
Chemours Co.		91,447		2,878,752
FMC Corp.		12,946		1,703,305
LyondellBasell Industries NV, Class A		42,193		4,338,284
Westlake Corp.		8,980		1,108,132
			$	11,434,028

Commercial Services — 1.48%
Global Payments, Inc.		4,188		573,086
ManpowerGroup, Inc.		20,632		1,937,757
Service Corp. International		17,258		1,135,922
			$	3,646,765

Computers — 3.01%
Genpact Ltd.		16,398		713,477
Hewlett Packard Enterprise Co.		161,945		2,706,101
HP, Inc.		54,403		1,974,829
Maximus, Inc.		15,105		1,132,119
TTEC Holdings, Inc.		10,588		873,722
			$	7,400,248

Distribution/Wholesale — 0.14%
LKQ Corp.		7,505		340,802

Diversified Financial Services — 11.11%
American Express Co.		4,575		855,525
Capital One Financial Corp.		9,905		1,300,427
Discover Financial Services		11,159		1,229,610
Evercore, Inc., Class A		13,013		1,448,607
Jefferies Financial Group, Inc.		55,281		1,815,981
Lazard Ltd.		106,247		3,665,522
Mastercard, Inc., Class A		1,144		408,843

See accompanying notes.

108


	Schedule of Investments
	Principal Value ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value

Diversified Financial Services (continued)
OneMain Holdings, Inc.		144,164	$	6,834,815
Synchrony Financial		37,558		1,307,394
T Rowe Price Group, Inc.		21,971		3,321,795
Visa, Inc., Class A		2,419		536,462
Western Union Co.		247,032		4,629,380
			$	27,354,361

Electric — 1.05%
NRG Energy, Inc.		67,545		2,591,026

Electronics — 0.36%
Allegion PLC		8,038		882,412

Environmental Control — 0.76%
Republic Services, Inc.		11,080		1,468,100
Tetra Tech, Inc.		2,425		399,980
			$	1,868,080

Food — 1.41%
Kroger Co.		31,193		1,789,542
Tyson Foods, Inc., Class A		18,828		1,687,554
			$	3,477,096

Hand/Machine Tools — 0.80%
Snap-on, Inc.		9,566		1,965,622

Healthcare — Products — 0.43%
Abbott Laboratories		8,987		1,063,701

Healthcare — Services — 1.54%
Anthem, Inc.		1,822		895,003
HCA Healthcare, Inc.		2,533		634,821
Quest Diagnostics, Inc.		9,026		1,235,298
UnitedHealth Group, Inc.		1,991		1,015,350
			$	3,780,472

Home Builders — 1.13%
Lennar Corp., Class A		8,115		658,695
Thor Industries, Inc.		18,846		1,483,180
Toll Brothers, Inc.		13,371		628,704
			$	2,770,579

Home Furnishings — 0.88%
Tempur Sealy International, Inc.		17,464		487,595
Whirlpool Corp.		9,780		1,689,788
			$	2,177,383

Insurance — 22.04%
Allstate Corp.		19,061		2,640,139
American Financial Group, Inc.		54,282		7,904,545
Chubb Ltd.		6,834		1,461,793
Fidelity National Financial, Inc.		53,155		2,596,090
First American Financial Corp.		31,332		2,030,940
Globe Life, Inc.		6,987		702,892
Hanover Insurance Group, Inc.		13,203		1,974,113
Hartford Financial Services Group, Inc.		25,333		1,819,163
Loews Corp.		5,982		387,753
MetLife, Inc.		38,119		2,679,003
Old Republic International Corp.		278,897		7,215,065

See accompanying notes.

109


	Schedule of Investments
	Principal Value ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value

Insurance (continued)
Primerica, Inc.		8,001	$	1,094,697
Progressive Corp.		50,139		5,715,345
Prudential Financial, Inc.		32,446		3,834,144
Reinsurance Group of America, Inc.		19,955		2,184,274
Selective Insurance Group, Inc.		12,800		1,143,808
Travelers Cos., Inc.		11,005		2,010,944
Unum Group		145,379		4,580,892
W R Berkley Corp.		34,320		2,285,369
			$	54,260,969

Internet — 0.39%
eBay, Inc.		16,805		962,254

Iron & Steel — 1.27%
Nucor Corp.		9,671		1,437,594
Steel Dynamics, Inc.		20,103		1,677,193
			$	3,114,787

Leisure Time — 0.37%
Brunswick Corp.		11,230		908,395

Machinery — Diversified — 2.69%
AGCO Corp.		29,119		4,252,248
Crane Co.		14,164		1,533,678
Toro Co.		9,823		839,768
			$	6,625,694

Media — 1.70%
Comcast Corp., Class A		35,278		1,651,716
Nexstar Media Group, Inc., Class A		8,487		1,599,630
Sirius XM Holdings, Inc.		142,674		944,502
			$	4,195,848

Mining — 1.48%
Newmont Corp.		45,696		3,630,547

Oil & Gas — 6.41%
ConocoPhillips		24,128		2,412,800
Coterra Energy, Inc.		215,257		5,805,481
Devon Energy Corp.		64,036		3,786,448
Diamondback Energy, Inc.		9,946		1,363,398
Marathon Oil Corp.		41,153		1,033,352
Ovintiv, Inc.		25,627		1,385,652
			$	15,787,131

Pharmaceuticals — 4.49%
AbbVie, Inc.		22,172		3,594,303
Bristol-Myers Squibb Co.		38,776		2,831,811
Cigna Corp.		6,209		1,487,739
McKesson Corp.		2,211		676,853
Pfizer, Inc.		47,676		2,468,187
			$	11,058,893

Pipelines — 2.54%
Kinder Morgan, Inc.		331,055		6,260,250

Real Estate — 0.07%
eXp World Holdings, Inc.		7,527		159,347

See accompanying notes.

110


	Schedule of Investments
	Principal Value ETF
	March 31, 2022 (unaudited)

COMMON STOCKS (continued)		Shares Held		Value
REITs — 8.38%
Highwoods Properties, Inc.		85,950	$	3,931,353
Lamar Advertising Co., Class A		25,613		2,975,718
SL Green Realty Corp.		90,896		7,378,937
VICI Properties, Inc.		139,756		3,977,456
Weyerhaeuser Co.		62,420		2,365,718
			$	20,629,182

Retail — 4.90%
Advance Auto Parts, Inc.		5,604		1,159,804
Dick's Sporting Goods, Inc. ^(a)		50,088		5,009,802
Kohl's Corp.		30,841		1,864,647
Penske Automotive Group, Inc.		14,298		1,340,008
Wendy's Co.		67,163		1,475,571
Williams-Sonoma, Inc.		8,366		1,213,070
			$	12,062,902

Semiconductors — 1.83%
Amkor Technology, Inc.		25,622		556,510
Broadcom, Inc.		3,231		2,034,496
KLA Corp.		2,209		808,627
Skyworks Solutions, Inc.		8,373		1,115,953
			$	4,515,586

Software — 0.33%
Concentrix Corp.		586		97,604
SS&C Technologies Holdings, Inc.		9,368		702,788
			$	800,392

Telecommunications — 1.07%
Corning, Inc.		54,060		1,995,355
Ubiquiti, Inc. ^(a)		2,183		635,602
			$	2,630,957

Transportation — 1.38%
Knight-Swift Transportation Holdings, Inc.		9,693		489,109
Norfolk Southern Corp.		4,606		1,313,723
Union Pacific Corp.		5,870		1,603,743
			$	3,406,575
TOTAL COMMON STOCKS			$	245,433,120


INVESTMENT COMPANIES — 0.49%		Shares Held		Value
Money Market Funds — 0.49%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(b),(c),(d),(e)}		660,419	$	660,419
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(e)		541,076		541,076
TOTAL INVESTMENT COMPANIES		$		1,201,495
Total Investments		$		246,634,615
Other Assets and Liabilities — (0.19)%				(457,446	)
Total Net Assets — 100.00%		$		246,177,169

^(a)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $634,828 or
	0.26% of net assets.
^(b)	Non-income producing security.
^(c)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of
	these securities totaled $660,419 or 0.27% of net assets.

See accompanying notes.

111


		Schedule of Investments
		Principal Value ETF
		March 31, 2022 (unaudited)

^(d)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate
	as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(e)	Current yield shown is as of period end.

	Portfolio Summary (unaudited)
Sector		Percent
Financial		45.40	%
Consumer, Non-cyclical		11.59	%
Industrial		9.57	%
Energy		8.96	%
Consumer, Cyclical		7.42	%
Basic Materials		7.38	%
Technology		5.17	%
Communications		3.16	%
Utilities		1.05	%
Money Market Funds		0.49	%
Other Assets and Liabilities		(0.19	)%
TOTAL NET ASSETS		100.00	%


			June 30, 2021		Purchases		Sales		March 31, 2022
Affiliated Securities			Value		Cost		Proceeds		Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$	1,202,967	$	542,548	$	660,419
		$	—	$	1,202,967	$	542,548	$	660,419

							Realized Gain
					Realized		from		Change in
					Gain/(Loss) on		Capital Gain		Unrealized
			Income ^(a)		Investments		Distributions		Gain/(Loss)
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$	—	$	—	$	—
		$	—	$	—	$	—	$	—

^(a)Amount excludes earnings from securities lending collateral.

See accompanying notes.

112

Principal Exchange-Traded Funds
March 31, 2022 (unaudited)

1. Security Valuation

The Funds value securities for which market quotations are readily available at fair value, which is determined using the last reported sale price. If no sales are reported, as is regularly the case for some securities traded over-the-counter, securities are valued using the last reported bid price or an evaluated bid price provided by a pricing service. Pricing services use modeling techniques that incorporate security characteristics such as current quotations by broker/dealers, coupon, maturity, quality, type of issue, trading characteristics, other yield and risk factors and other market conditions to determine an evaluated bid price. When reliable market quotations are not considered to be readily available, which may be the case, for example, with respect to restricted securities, certain debt securities, preferred stocks, and foreign securities, the investments are valued at their fair value as determined in good faith by the Principal Global Investors, LLC, ("the Advisor") under procedures established and periodically reviewed by the Board of Trustees. The Funds may invest in series of Principal Funds, Inc. and other investment funds, which may include money market funds and other registered open-end investment companies. Investments in registered open-end investment companies are valued at the respective fund's closing net asset value ("NAV") per share on the day of valuation.

The value of foreign securities used in computing the NAV per share is generally determined as of the close of the foreign exchange where the security is principally traded. Events that occur after the close of the applicable foreign market or exchange but prior to the calculation of the Fund’s NAV are reflected in the Fund’s NAV and these securities are valued at fair value. Many factors, provided by independent pricing services, are reviewed in the course of making a good faith determination of a security’s fair value including, but not limited to, price movements in American Depository Receipts (“ADRs”), futures contracts, industry indices, general indices, and foreign currencies.

To the extent the Funds invest in foreign securities listed on foreign exchanges which trade on days on which the Funds do not determine NAV, for example, weekends and other customary national U.S. holidays, the Fund’s NAV could be significantly affected on days when shares are not able to be issued or redeemed by Authorized Participants (“APs”).

Certain securities issued by companies in emerging market countries may have more than one quoted valuation at any given point in time, sometimes referred to as a “local” price and a “premium” price. The premium price is often a negotiated price, which may not consistently represent a price at which a specific transaction can be effected. It is the policy of the Funds to value such securities at prices at which it is expected those shares may be sold, and the Advisor, or any sub-advisor, is authorized to make such determinations subject to such oversight by the Board of Trustees, as may occasionally be necessary.

2. Fair Valuation

Fair value is defined as the price that the Funds would receive upon selling a security or transferring a liability in a timely transaction to an independent buyer in the principal or most advantageous market of the security at the measurement date. In determining fair value, the Funds may use one or more of the following approaches: market, income and/or cost. A hierarchy for inputs is used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available.

Observable inputs are inputs that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the Funds. Unobservable inputs are inputs that reflect the Fund’s own estimates about the estimates market participants would use in pricing the asset or liability developed based on the best information available in the circumstances.

The three-tier hierarchy of inputs is summarized in the three broad levels listed below.

Level 1 — Quoted prices are available in active markets for identical securities as of the reporting date. Investments which are generally included in this category include listed equities and listed derivatives.

Level 2 — Other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, credit risk, etc.). Investments which are generally included in this category include certain corporate bonds, senior floating rate interests, over-the-counter (“OTC”) derivatives, mortgage-backed securities and municipal bonds.

113

Principal Exchange-Traded Funds
March 31, 2022 (unaudited) (continued)

2. Fair Valuation (continued)

Level 3 — Significant unobservable inputs (including the Funds’ assumptions in determining the fair value of investments). Investments which are generally included in this category include certain corporate bonds and certain common stocks.

The availability of observable inputs can vary from security to security and is affected by a wide variety of factors, including, for example, the type of security, whether the security is new and not yet established in the market place, and other characteristics particular to the transaction. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Funds in determining fair value is greatest for instruments categorized in Level 3.

In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the level in the fair value hierarchy within which the fair value measurement in its entirety falls is determined based on the lowest level input that is significant to the fair value measurement in its entirety.

Fair value is a market based measure considered from the perspective of a market participant who holds the asset rather than an entity specific measure. Therefore, even when market assumptions are not readily available, the Funds’ own assumptions are set to reflect those that market participants would use in pricing the asset or liability at the measurement date. The Funds use prices and inputs that are current as of the measurement date, to the extent available.

Investments which are included in the Level 3 category may be valued using quoted prices from brokers and dealers participating in the market for these investments. These investments are classified as Level 3 investments due to the lack of market transparency and market corroboration to support these quoted prices.

Valuation models may be used as the pricing source for other investments classified as Level 3. Valuation models rely on one or more significant unobservable inputs such as prepayment rates, probability of default, or loss severity in the event of default. Significant increases in any of those inputs in isolation would result in a significantly lower fair value measurement.

The fair values of these entities are dependent on economic, political and other considerations. The values of the underlying investee entities may be affected by significant changes in the economic conditions, changes in government policies, and other factors (e.g., natural disasters, pandemics, accidents, conflicts, etc.).

The inputs or methodology used for valuing securities are not necessarily an indication of the risk associated with investing in those instruments.

During the period there were no significant purchases, sales, or transfers into or out of Level 3.

The following is a summary of the inputs used as of March 31, 2022, in valuing the Funds' securities carried at fair value:


				Level 2 —
				Other		Level 3 —
		Level 1 —		Significant		Significant
		Quoted		Observable		Unobservable
Fund		Prices		Inputs		Inputs		Totals (Level 1,2,3)

Principal Active High Yield ETF
Common Stocks*	$	659,083	$	— $			— $	659,083
Bonds*		—		200,342,670			—	200,342,670
Senior Floating Rate Interests*		—		23,971,180			—	23,971,180
Investment Companies		6,455,523		—			—	6,455,523
Total investments in securities	$	7,114,606	$	224,313,850	$		— $	231,428,456

114


Principal Exchange-Traded Funds
March 31, 2022 (unaudited) (continued)



2. Fair Valuation (continued)


				Level 2 —
				Other		Level 3 —
		Level 1 —		Significant		Significant
		Quoted		Observable		Unobservable
Fund		Prices		Inputs		Inputs		Totals (Level 1,2,3)

Principal Healthcare Innovators ETF
Common Stocks*	$	71,289,337	$	— $			— $	71,289,337
Investment Companies		2,021,199		—			—	2,021,199
Total investments in securities	$	73,310,536	$	— $			— $	73,310,536

Principal International Adaptive Multi-Factor ETF
Common Stocks*	$	42,004,585	$	— $			— $	42,004,585
Preferred Stocks*		35,778		—			—	35,778
Investment Companies		268,501		—			—	268,501
Total investments in securities	$	42,308,864	$	— $			— $	42,308,864

Principal Investment Grade Corporate Active ETF
Bonds*	$	— $		407,505,515	$		— $	407,505,515
Investment Companies		1,917,266		—			—	1,917,266
Total investments in securities	$	1,917,266	$	407,505,515	$		— $	409,422,781
Derivatives
Assets
Interest rate contracts
Futures	$	509,686	$	— $			— $	509,686
Derivatives
Liabilities
Interest rate contracts
Futures	$	(137,978	) $	— $			— $	(137,978	)

Principal Millennials ETF
Common Stocks*	$	26,651,748	$	— $			— $	26,651,748
Investment Companies		324,300		—			—	324,300
Total investments in securities	$	26,976,048	$	— $			— $	26,976,048

Principal Quality ETF
Common Stocks*	$	85,729,312	$	— $			— $	85,729,312
Investment Companies		176,068		—			—	176,068
Total investments in securities	$	85,905,380	$	— $			— $	85,905,380

Principal Spectrum Preferred Securities Active ETF
Bonds*	$	— $		384,750,327	$		— $	384,750,327
Investment Companies		6,053,895		—			—	6,053,895
Total investments in securities	$	6,053,895	$	384,750,327	$		— $	390,804,222

Principal Spectrum Tax-Advantaged Dividend Active ETF
Preferred Stocks*	$	2,608,492	$	— $			— $	2,608,492
Bonds*		—		19,695,174			—	19,695,174
Investment Companies		259,769		—			—	259,769
Total investments in securities	$	2,868,261	$	19,695,174	$		— $	22,563,435

Principal Ultra-Short Active Income ETF
Bonds*	$	— $		8,238,530	$		— $	8,238,530
Investment Companies		289,613		—			—	289,613
Total investments in securities	$	289,613	$	8,238,530	$		— $	8,528,143

Principal U.S. Large-Cap Adaptive Multi-Factor ETF
Common Stocks*	$	102,437,757	$	— $			— $	102,437,757
Investment Companies		246,900		—			—	246,900
Total investments in securities	$	102,684,657	$	— $			— $	102,684,657

Principal U.S. Mega-Cap ETF
Common Stocks*	$	1,630,113,766	$	— $			— $	1,630,113,766
Investment Companies		5,339,042		—			—	5,339,042
Total investments in securities	$	1,635,452,808	$	— $			— $	1,635,452,808

115


Principal Exchange-Traded Funds
March 31, 2022 (unaudited) (continued)



2. Fair Valuation (continued)

				Level 2 —
				Other	Level 3 —
		Level 1 —		Significant	Significant
		Quoted		Observable	Unobservable
Fund		Prices		Inputs	Inputs		Totals (Level 1,2,3)

Principal U.S. Small-Cap Adaptive Multi-Factor ETF
Common Stocks*	$	6,244,647	$	— $		— $	6,244,647
Investment Companies		15,535		—		—	15,535
Total investments in securities	$	6,260,182	$	— $		— $	6,260,182

Principal U.S. Small-Cap Multi-Factor ETF
Common Stocks*	$	768,876,254	$	— $		— $	768,876,254
Investment Companies		9,250,796		—		—	9,250,796
Total investments in securities	$	778,127,050	$	— $		— $	778,127,050

Principal Value ETF
Common Stocks*	$	245,433,120	$	— $		— $	245,433,120
Investment Companies		1,201,495		—		—	1,201,495
Total investments in securities	$	246,634,615	$	— $		— $	246,634,615

* For additional detail regarding sector classifications, please see the Schedules of Investments.

The Fund’s Schedules of Investments for the period ended March 31, 2022 has not been audited. This report is provided for the general information of the Fund’s shareholders. For more information regarding the Funds and their holdings, please see the F

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