September 10, 2012

U.S. Securities & Exchange Commission
100 F Street, N.E.
Washington, DC 20549

Re: Vanguard Money Market Reserves (the “Trust”); File No. 2-52698

Commissioners:

Pursuant to Rule 497(e) under the Securities Act of 1933, we hereby file exhibits containing
interactive data format risk/return summary information that reflects the risk/return summary
information in the supplement dated August 31, 2012, filed pursuant to Rule 497(e), for the
Vanguard Federal Money Market Fund, a series of the above mentioned Trust.

If you have any questions or comments concerning the foregoing, please contact me at
(610) 669-1955.

Sincerely,

Tara R. Buckley
Senior Counsel
The Vanguard Group, Inc.