Form 485BXT DFA INVESTMENT DIMENSION

December 5, 2025 1:27 PM EST
As filed with the U.S. Securities and Exchange Commission on December 5, 2025
File No. 002-73948
File No. 811-03258
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C.  20549
FORM N-1A
 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
 [X]
 
Pre-Effective Amendment No. __
 [  ]
 
Post-Effective Amendment No. 264
  [X]
     
and/or
     
 REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940
 [X]
   Amendment No. 266
 
(Check appropriate box or boxes.)
DFA INVESTMENT DIMENSIONS GROUP INC.
(Exact Name of Registrant as Specified in Charter)
6300 Bee Cave Road, Building One, Austin, TX      78746
(Address of Principal Executive Office)             (Zip Code)
Registrant’s Telephone Number, including Area Code  (512) 306-7400
Catherine L. Newell, Esquire, President and General Counsel
DFA Investment Dimensions Group Inc.,
6300 Bee Cave Road, Building One, Austin, TX 78746
(Name and Address of Agent for Service)
Please send copies of all communications to:
Jana L. Cresswell, Esquire
Brian Crowell, Esquire
Stradley Ronon Stevens & Young, LLP
2600 One Commerce Square
Philadelphia, PA 19103
(215) 564-8048
It is proposed that this filing will become effective (check appropriate box):
[   ] immediately upon filing pursuant to paragraph (b)
[X] on January 7, 2026 pursuant to paragraph (b)
[   ] 60 days after filing pursuant to paragraph (a)(1)
[   ] on [Date] pursuant to paragraph (a)(1)
[   ] 75 days after filing pursuant to paragraph (a)(2)
[   ] on [Date] pursuant to paragraph (a)(2) of Rule 485
If appropriate, check the following box:
[X] This post-effective amendment designates a new effective date for a previously filed post-effective amendment.
Titles of Securities Being Registered:
U.S. Large Cap Equity Portfolio: ETF Class shares
U.S. Small Cap Value Portfolio: ETF Class shares
U.S. Targeted Value Portfolio: ETF Class shares
U.S. Core Equity 1 Portfolio: ETF Class shares
U.S. Core Equity 2 Portfolio: ETF Class shares
U.S. Vector Equity Portfolio: ETF Class shares
U.S. Small Cap Portfolio: ETF Class shares
U.S. Micro Cap Portfolio: ETF Class shares
U.S. High Relative Profitability Portfolio: ETF Class shares
DFA Real Estate Securities Portfolio: ETF Class shares
U.S. Large Cap Growth Portfolio: ETF Class shares
U.S. Small Cap Growth Portfolio: ETF Class shares
This Post-Effective Amendment No. 264/266 to Registration File Nos. 002-73948/811-03258 includes the following:
1. FACING PAGE
2. CONTENTS PAGE
3.
PART A – Prospectus relating to the ETF Class shares of the Registrant’s U.S. Large Cap Equity Portfolio, U.S. Small Cap Value Portfolio, U.S. Targeted Value Portfolio, U.S. Core Equity 1 Portfolio, U.S. Core Equity 2 Portfolio, U.S. Vector Equity Portfolio, U.S. Small Cap Portfolio, U.S. Micro Cap Portfolio, U.S. High Relative Profitability Portfolio, DFA Real Estate Securities Portfolio, U.S. Large Cap Growth Portfolio, and U.S. Small Cap Growth Portfolio series of shares
4.
PART B – Statement of Additional Information relating to the ETF Class shares of the Registrant’s U.S. Large Cap Equity Portfolio, U.S. Small Cap Value Portfolio, U.S. Targeted Value Portfolio, U.S. Core Equity 1 Portfolio, U.S. Core Equity 2 Portfolio, U.S. Vector Equity Portfolio, U.S. Small Cap Portfolio, U.S. Micro Cap Portfolio, U.S. High Relative Profitability Portfolio, DFA Real Estate Securities Portfolio, U.S. Large Cap Growth Portfolio, and U.S. Small Cap Growth Portfolio series of shares
5. PART C – Other Information
6. SIGNATURES
*
The Prospectus and Statement of Additional Information relating to the ETF Class shares of the Portfolios are incorporated into this filing by reference to the electronic filing of Post-Effective Amendment Nos. 263/265 to the Registration Statement of the Registrant, which was filed with the U.S. Securities and Exchange Commission (“SEC”) via the EDGAR system pursuant to Rule 485(a)(1) on October 9, 2025 (Accession Number 0000355437-25-000009).
EXPLANATORY NOTE

Post-Effective Amendment Nos. 263/265 (“PEA 263/265”) was filed with the U.S. Securities and Exchange Commission (“SEC”) via the EDGAR system pursuant to Rule 485(a)(1) on October 9, 2025 (Accession Number 0000355437-25-000009) to be effective 60 days after filing.

Pursuant to Rule 485(b)(1)(iii) of the Securities Act of 1933, as amended, this Post-Effective Amendment Nos. 264/266 (“PEA 264/266”) to the Registration Statement of DFA Investment Dimensions Group Inc. (the “Registrant”) is being filed solely for the purpose of delaying the effectiveness of PEA 263/265 relating to the ETF Class shares of U.S. Large Cap Equity Portfolio, U.S. Small Cap Value Portfolio, U.S. Targeted Value Portfolio, U.S. Core Equity 1 Portfolio, U.S. Core Equity 2 Portfolio, U.S. Vector Equity Portfolio, U.S. Small Cap Portfolio, U.S. Micro Cap Portfolio, U.S. High Relative Profitability Portfolio, DFA Real Estate Securities Portfolio, U.S. Large Cap Growth Portfolio and U.S. Small Cap Growth Portfolio, each a series of the Registrant (the “Portfolios”). This PEA 264/266 relates only to the ETF Class shares of the Portfolios and does not otherwise delete, amend, or supersede any information relating to any other series or class of the Registrant.

Accordingly, the Prospectus and Statement of Additional Information of the Registrant as filed in PEA 263/265 are incorporated herein by reference in their entirety into this filing. As stated on the cover page to this filing, this PEA 264/266 is being filed for the sole purpose of designating January 7, 2026 as the new date upon which PEA 263/265 shall become effective.
DFA INVESTMENT DIMENSIONS GROUP INC. (264/266)

PART C
OTHER INFORMATION

ITEM 28. EXHIBITS.

(a) Articles of Incorporation.


 (1)


(2)


(3)


(4)


(5)


(6)


(7)


(8)


(9)


(10)


(11)


(12)


(13)


(14)


(15)


(16)


(17)


(18)


(19)


(20)


(21)


(22)


(23)


(24)


(25)


(26)


(27)


(28)


(29)


(30)


(31)


(32)


(33)


(34)


(35)

(36)


(37)


(38)


(39)


(40)


(41)


(42)


(43)


(45)


(46)


(47)


(48)




(52)


(53)


(54)


(55)





(b)
By-Laws.

(c)
Instruments Defining the Rights of Security holders.


(1)


(2)

(d)
Investment Advisory Agreements.


(1)
Investment Management Agreements.


(a)

*


(b)

*


(c)

*


(d)


(e)


(f)


(g)


(h)


(i)


(j)


(k)


(l)


(m)


(n)


(o)


(p)


(q)


(r)


(s)


(t)


(u)


(v)


(w)


(x)


(y)


(z)


(aa)


(bb)


(cc)


(dd)


(ee)


(ff)


(gg)


(hh)


(ii)


(jj)


(kk)


(ll)


(mm)


(nn)


(oo)


(pp)


(qq)


(rr)


(ss)


(tt)


(uu)


(vv)


(ww)


(xx)


(yy)


(zz)


(aaa)


(bbb)


(ccc)


(ddd)


(eee)


(fff)


(ggg)


(hhh)


(iii)


(jjj)


(kkk)


(lll)


(mmm)


(nnn)


(ooo)


(ppp)


(qqq)


(rrr)


(sss)


(ttt)


(uuu)


(vvv)


(www)


(xxx)


(yyy)


(zzz)


(aaaa)


(bbbb)


(cccc)


(dddd)


(eeee)


(ffff)


(gggg)



(iiii)




(llll)



(nnnn)


(oooo)



(qqqq)




(tttt)


(uuuu)


(vvvv)


(wwww)


(xxxx)




(2)
Sub-advisory Agreements.


(a)

*


(1)


(b)

*


(c)


(d)


(e)

*


(f)

*


(g)

*


(h)

*


(i)

*


(j)

*


(k)

*


(l)

*


(m)

*


(n)

*


(o)

*


(p)

*


(q)

*


(r)

*


(s)

*


(t)


(u)

*


(v)

*


(w)

*


(x)

*


(y)

*


(z)

*


(aa)

*


(bb)

*


(cc)

*


(dd)

*


(ee)

*


(ff)

*


(gg)

*


(hh)

*


(ii)

*


(jj)

*


(kk)

*


(ll)

*


(mm)

*


(nn)

*


(oo)

*


(pp)

*


(qq)


(rr)


(ss)


(tt)


(uu)


(vv)


(ww)


(xx)


(yy)


(zz)


(aaa)


(bbb)


(ccc)


(ddd)


(eee)


(fff)


(ggg)


(hhh)


(iii)


(jjj)


(kkk)


(lll)


(mmm)


(nnn)


(ooo)


(ppp)


(qqq)


(rrr)


(sss)


(ttt)


(uuu)


(vvv)


(www)


(xxx)


(yyy)


(zzz)


(aaaa)


(bbbb)


(cccc)


(dddd)


(eeee)


(ffff)


(gggg)


(hhhh)


(iiii)


(jjjj)


(kkkk)


(llll)


(mmmm)


(nnnn)




(e)
Underwriting Contracts.


(1)

(f)
Bonus or Profit Sharing Plans.

Not Applicable.

(g)
Custodian Agreements.


(1)


(a)


(b)


(c)


(d)


(2)


(a)


(b)


(c)


(d)

(h)
Other Material Contracts.


(1)


(a)


(b)


(c)


(d)


(e)




(2)


(3)


(a)


(b)



(4) Other.


(a)


(b)


(c)


(1)


(d)


(e)


(f)




(g)


(h)


(i)


(j)


(i)
Legal Opinion.


(1)

(j)
Other Opinions.

(1)


(2)
Consent of Independent Registered Public Accounting Firm relating to ETF Class shares of certain Portfolios to be filed by Amendment.

(k)
Omitted Financial Statements.

Not Applicable.

(l)
Initial Capital Agreements.

Subscription Agreement under Section 14(a)(3) of the Investment Company Act of 1940. Previously filed with this registration statement and incorporated herein by reference.

(m)
Rule 12b-1 Plans.

Not Applicable.

(n)
Plans pursuant to Rule 18f-3.


(1)

(o)
Powers-of-Attorney.


(1)



(2)


(3)


(4)

(p)
Codes of Ethics.


(1)

ITEM 29.   PERSONS CONTROLLED BY OR UNDER COMMON CONTROL WITH THE REGISTRANT.

(a)
DFA Commodity Strategy Portfolio, a series of the Registrant, wholly owns and controls Dimensional Cayman Commodity Fund I Ltd. (the “DFA Cayman Subsidiary”); a company organized under the laws of the Cayman Islands. The DFA Cayman Subsidiary’s financial statements are and will be included on a consolidated basis in the DFA Investment Dimensions Group Inc’s annual and semi-annual reports to shareholders.

ITEM 30.   INDEMNIFICATION.

Reference is made to Section 1 of Article IX of the Registrant’s Amended and Restated By-Laws, which provide for indemnification, as set forth below.

With respect to the indemnification of the Officers and Directors of the Corporation:


 (a)
The Corporation shall indemnify each Officer and Director made party to a proceeding, by reason of service in such capacity, to the fullest extent, and in the manner provided, under Section 2-418 of the Maryland General Corporation Law: (i) unless it is proved that the person seeking indemnification did not meet the standard of conduct set forth in subsection (b)(1) of such section; and (ii) provided, that the Corporation shall not indemnify any officer or Director for any liability to the Corporation or its security holders arising from the willful misfeasance, bad faith, gross negligence or reckless disregard of the duties involved in the conduct of such person’s office.


(b)
The provisions of clause (i) of paragraph (a) herein notwithstanding, the Corporation shall indemnify each Officer and Director against reasonable expenses incurred in connection with the successful defense of any proceeding to which such Officer or Director is a party by reason of
service in such capacity.


 (c)
The Corporation, in the manner and to the extent provided by applicable law, shall advance to each Officer and Director who is made party to a proceeding by reason of service in such capacity the reasonable expenses incurred by such person in connection therewith.

ITEM 31.   BUSINESS AND OTHER CONNECTIONS OF THE INVESTMENT ADVISOR.


(a)
Dimensional Fund Advisors LP, with a principal place of business located at 6300 Bee Cave Road, Building One, Austin TX 78746, the investment manager for the Registrant, is also the investment manager for four other registered open-end investment companies, The DFA Investment Trust Company, Dimensional Emerging Markets Value Fund, Dimensional Investment Group Inc. and Dimensional ETF Trust. The Advisor also serves as sub-advisor for certain other registered investment companies.

The Advisor is engaged in the business of providing investment advice primarily to institutional investors. For additional information, please see “Management of the Fund” in PART A and “Directors and Officers” in PART B of this Registration Statement.

Additional information as to the Advisor and the partners and executive officers of the Advisor is included in the Advisor’s Form ADV filed with the Commission (File No. 801-16283), which is incorporated herein by reference and sets forth the executive officers and partners of the Advisor and information as to any business, profession, vocation or employment or a substantial nature engaged in by those officers and partners during the past two years.


 (b)
The Sub-Advisor for the Dimensional VA International Small Portfolio, International Core Equity 2 Portfolio, Emerging Markets Social Core Equity Portfolio, DFA International Real Estate Securities Portfolio, International Sustainability Core 1 Portfolio, DFA Selectively Hedged Global Fixed Income Portfolio, DFA Global Real Estate Securities Portfolio, International Vector Equity Portfolio, DFA Short-Term Extended Quality Portfolio, DFA Intermediate-Term Extended Quality Portfolio, DFA International Small Cap Value Portfolio, Large Cap International Portfolio, Emerging Markets Core Equity 2 Portfolio, World ex U.S. Value Portfolio, DFA Commodity Strategy Portfolio, DFA Investment Grade Portfolio, World Core Equity Portfolio, DFA LTIP Portfolio, Selectively Hedged Global Equity Portfolio, DFA World ex U.S. Government Fixed Income Portfolio, International Social Core Equity Portfolio, World ex U.S. Targeted Value Portfolio, International Large Cap Growth Portfolio, International Small Cap Growth Portfolio, World ex U.S. Core Equity Portfolio, DFA Short-Duration Real Return Portfolio, DFA Targeted Credit Portfolio, DFA One-Year Fixed Income Portfolio, DFA Two-Year Global Portfolio, DFA Five-Year Global Portfolio, VA Short-Term Fixed Income Portfolio, VA Global Bond Portfolio, DFA Social Fixed Income Portfolio, DFA Diversified Fixed Income Portfolio, Global Small Company Portfolio, International High Relative Profitability Portfolio, Dimensional VA Equity Allocation Portfolio, DFA Global Core Plus Fixed Income Portfolio, Emerging Markets Sustainability Core 1 Portfolio, Emerging Markets Targeted Value Portfolio, DFA Global Sustainability Fixed Income Portfolio, Dimensional VA International Value Portfolio, Global Social Core Equity Portfolio, DFA Global Core Plus Real Return Portfolio,

Emerging Markets ex China Core Equity Portfolio, and Dimensional World ex U.S. Sustainability Targeted Value Portfolio, each a series of the Registrant, is Dimensional Fund Advisors Ltd. (“DFAL”). DFAL has its principal place of business is 20 Triton Street, Regent’s Place, London, NW13BF, United Kingdom. Additional information as to the DFAL and the directors and officers of DFAL is included in the DFAL’s Form ADV filed with the Commission (File No. 801-40136), which is incorporated herein by reference and sets forth the officers and directors of DFAL and information as to any business, profession, vocation or employment or a substantial nature engaged in by those officers and directors during the past two years.


 (c)
The Sub-Advisor for the Dimensional VA International Small Portfolio, International Core Equity 2 Portfolio, Emerging Markets Social Core Equity Portfolio, DFA International Real Estate Securities Portfolio,  International Sustainability Core 1 Portfolio, DFA Selectively Hedged Global Fixed Income Portfolio, DFA Global Real Estate Securities Portfolio, International Vector Equity Portfolio, DFA Short-Term Extended Quality Portfolio, DFA Intermediate-Term Extended Quality Portfolio, DFA International Small Cap Value Portfolio, Large Cap International Portfolio, Emerging Markets Core Equity 2 Portfolio, World ex U.S. Value Portfolio, DFA Commodity Strategy Portfolio, DFA Investment Grade Portfolio, World Core Equity Portfolio, DFA LTIP Portfolio, Selectively Hedged Global Equity Portfolio, DFA World ex U.S. Government Fixed Income Portfolio, International Social Core Equity Portfolio, World ex U.S. Targeted Value Portfolio, International Large Cap Growth Portfolio, International Small Cap Growth Portfolio, World ex U.S. Core Equity Portfolio, DFA Short-Duration Real Return Portfolio, DFA Targeted Credit Portfolio, DFA One-Year Fixed Income Portfolio, DFA Two-Year Global Portfolio, DFA Five-Year Global Portfolio, VA Short-Term Fixed Income Portfolio, VA Global Bond Portfolio, DFA Social Fixed Income Portfolio, DFA Diversified Fixed Income Portfolio, Global Small Company Portfolio, International High Relative Profitability Portfolio, Dimensional VA Equity Allocation Portfolio, DFA Global Core Plus Fixed Income Portfolio, Emerging Markets Sustainability Core 1 Portfolio, Emerging Markets Targeted Value Portfolio, DFA Global Sustainability Fixed Income Portfolio, Dimensional VA International Value Portfolio, Global Social Core Equity Portfolio, DFA Global Core Plus Real Return Portfolio, Emerging Markets ex China Core Equity Portfolio, and Dimensional World ex U.S. Sustainability Targeted Value Portfolio, each a series of the Registrant, is DFA Australia Limited (“DFA Australia”). DFA Australia has its principal place of business is Level 43 Gateway, 1 MacQuarie Place, Sydney, New South Wales 2000, Australia. Additional information as to DFA Australia and the directors and officers of DFA Australia is included in DFA Australia’s Form ADV filed with the Commission (File No. 801-48036), which is incorporated herein by reference and sets forth the officers and directors of DFA Australia and information as to any business, profession, vocation or employment or a substantial nature engaged in by those officers and directors during the past two years.

ITEM 32.   PRINCIPAL UNDERWRITERS.


(a)
DFA Securities LLC, (“DFAS”) is the principal underwriter for the Registrant. DFAS also serves as principal underwriter for The DFA Investment Trust Company, Dimensional Emerging Markets Value Fund, Dimensional Investment Group Inc. and Dimensional ETF Trust.


(b)
The following table sets forth information as to the Distributor’s Officers, Partners and Control Persons. The address of each officer is 6300 Bee Cave Road, Austin, Texas 78746:

Name and Principal Business Address
Positions and Offices with Underwriter
Positions and Offices with Fund
Valerie A. Brown
Vice President and Assistant Secretary
Vice President and Assistant Secretary
Ryan P. Buechner
Not Applicable
Vice President and Assistant Secretary
David P. Butler
Co-Chief Executive Officer
Co-Chief Executive Officer and Director
Stephen A. Clark
Executive Vice President
Executive Vice President
Lisa M. Dallmer
Executive Vice President and Chief Operating Officer
Chief Operating Officer

Bernard J. Grzelak
Vice President, Chief Financial Officer, and Treasurer
Vice President
Jeff J. Jeon
Vice President
Vice President
Joy L. Lopez
Not Applicable
Vice President and Assistant Treasurer
Kenneth M. Manell
Not Applicable
Vice President
Jan Miller
Not Applicable
Vice President, Chief Financial Officer and Treasurer
Catherine L. Newell
Executive Vice President, Secretary and General Counsel
President and General Counsel
Selwyn Notelovitz
Vice President and Chief Compliance Officer
Vice President
Carolyn S. Lee
Vice President and Assistant Secretary
Vice President and Secretary
Randy C. Olson
Vice President
Chief Compliance Officer
Gerard K. O’Reilly
Co-Chief Executive Officer and Co-Chief Investment Officer
Co-Chief Executive Officer, Co-Chief Investment Officer, Chairman and Director
Savina B. Rizova
Vice President and Co-Chief Investment Officer
Co-Chief Investment Officer
James J. Taylor
Not Applicable
Vice President and Assistant Treasurer
Dimensional Fund Advisors LP
Sole Member
Not Applicable


(c)
Not applicable.

ITEM 33.   LOCATION OF ACCOUNTS AND RECORDS.

The accounts and records of the Registrant are located at the office of the Registrant and at additional locations, as follows:

 
Name
Address
 
DFA Investment Dimensions Group Inc.
6300 Bee Cave Road,
Building One
Austin, TX 78746
     
 
State Street Bank and Trust Company
One Congress Street, Suite 1,
Boston, MA 02114-2016
     
 
Citibank, N.A.
111 Wall Street
New York, New York 10005
     
 
SS&C GIDS, Inc.
1055 Broadway Boulevard
Kansas City, MO 64105

ITEM 34.   MANAGEMENT SERVICES.

None.
ITEM 35.   UNDERTAKINGS.

Not Applicable.


SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all of the requirements for effectiveness of this registration statement under rule 485(b) under the Securities Act and has duly caused this Post-Effective Amendment Nos. 264/266 to the Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Austin, the State of Texas, as of this 5th day of December, 2025.

 
DFA INVESTMENT DIMENSIONS GROUP INC.
 
(Registrant)
 
By:
/s/Catherine L. Newell* 
   
Catherine L. Newell, President
   
(Signature and Title)

Pursuant to the requirements of the Securities Act of 1933, Post-Effective Amendment Nos. 264/266 to this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.

Signature
Title
Date
     
/s/ Gerard K. O’Reilly*
Co-Chief Executive Officer, Co-Chief Investment Officer, Chairman and Director
December 5, 2025
Gerard K. O’Reilly
     
/s/ David P. Butler*
David P. Butler
Co-Chief Executive Officer and Director
December 5, 2025
     
/s/ Jan Miller*
Jan Miller
Chief Financial Officer (Principal Financial Officer), Treasurer (Principal Accounting Officer) and Vice President
December 5, 2025
     
/s/ Reena Aggarwal*
Director
December 5, 2025
Reena Aggarwal
    
     
/s/ Douglas W. Diamond*
Director
December 5, 2025
Douglas W. Diamond
    
     
/s/ Darrell Duffie*
Director
December 5, 2025
Darrell Duffie
    
     
/s/ Francis A. Longstaff*
Director
December 5, 2025
Francis A. Longstaff
    
     
/s/ Stefan Nagel*
Director
December 5, 2025
Stefan Nagel
    
     
/s/ Abbie J. Smith*
Director
December 5, 2025
Abbie J. Smith
    
     
/s/ Heather E. Tookes*
Director
December 5, 2025
Heather E. Tookes
    
     
/s/ Ingrid M. Werner*
Director
December 5, 2025
Ingrid M. Werner
    

* By:   /s/ Ryan P. Buechner
Ryan P. Buechner
Attorney-in-Fact (Pursuant to a Power-of-Attorney)

EXHIBIT LIST
Exhibit No.
Description

There are no exhibits filed with this Registratrion Statement.

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