Form 485BXT VANGUARD CMT FUNDS

Explanatory Note

This Post-Effective Amendment No. 37 under the Securities Act of 1933, as amended (the "Securities Act") (Amendment No. 38 under the Investment Company Act of 1940, as amended (the "1940 Act")) to the registration statement on Form N-1A (the "Registration Statement") of Vanguard CMT Funds (the "Trust") is being filed pursuant to paragraph (b)(1)(iii) of Rule 485 under the Securities Act solely for the purpose of delaying, until June 5, 2024, the pending effective date of the Trust's 36th Post-Effective Amendment.

For background, Post-Effective Amendment No. 36 was filed under Rule 485(a)(1) on March 19, 2024, in connection with the conversion of (1) Vanguard Market Liquidity Fund from a prime institutional money market fund to a government money market fund and (2) Vanguard Municipal Cash Management Fund from a municipal money market fund to a municipal short term bond fund, to be named Vanguard Municipal Low Duration Fund. Post-Effective Amendment No. 36 would have become effective on May 20, 2024.

This Post-Effective Amendment No. 37 incorporates by reference the information contained in Parts A, B, and C of Post-Effective Amendment No. 36 to the Registrant's Registration Statement.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant hereby certifies that it meets all requirements for effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the Town of Valley Forge and the Commonwealth of Pennsylvania, on the 14th day of May, 2024.

VANGUARD CMT FUNDS

BY: /s/ Mortimer J. Buckley*

Mortimer J. Buckley

Chairman and Chief Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment to the Registration Statement has been signed below by the following persons in the capacities and on the date indicated:

*By: /s/ Anne E. Robinson

Anne E. Robinson, pursuant to a Power of Attorney filed on January 11, 2024 (see File Number 33-34494); a Power of Attorney filed on July 21, 2023 (see File Number 33-53683); and a Power of Attorney filed on March 29, 2023 (see File Number 2-11444), each Incorporated by Reference.