American Century Capital Value Fund Investor Class (ACTIX) DEFA14A Additional proxy soliciting materials

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the Securities

Exchange Act of 1934 (Amendment No.          )

Filed by the Registrant	T
Filed by a Party other than the Registrant	£

Check the appropriate box:

£	Preliminary Proxy Statement
£	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))
£	Definitive Proxy Statement
T	Definitive Additional Materials
£	Soliciting Materials Pursuant to §240.14a-12

AMERICAN CENTURY MUTUAL FUNDS, INC.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant

Payment of Filing Fee (Check the appropriate box):

T	No Fee required.
£	Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.
	1)	Title of each class of securities to which transaction applies:
	2)	Aggregate number of securities to which transaction applies:
	3)	Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (set forth the amount on which the filing fee is calculated and state how it was determined):
	4)	Proposed maximum aggregate value of transaction:
	5)	Total fee paid:

£	Fee paid previously with preliminary materials.
£	Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously.  Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.
	1)	Amount Previously Paid:
	2)	Form, Schedule or Registration Statement No.:
	3)	Filing Party:
	4)	Date Filed:

May 17, 2010

Recently, we sent you proxy materials for the Special Meeting of Shareholders to take place on June 16, 2010.  Our records indicate that we have not received your important vote on the proposals presented to shareholders as outlined below.  We urge you to vote today in order to allow us to obtain a sufficient number of votes to hold the Meeting as scheduled and avoid future reminders and the possibility of an adjournment.

Proposals:

·   Electing one nominated Director/Trustee to each Board of Directors/Trustees

Each nominee currently serves as an appointed director/trustee, but has not previously been elected by shareholders.

·   Approving a management agreement with American Century Investment Management, Inc. and a subadvisory agreement for Equity Index Fund and International Value Fund

On February 16, 2010, Co-Chairman Richard W. Brown succeeded James E. Stowers, Jr., the founder of American Century Investments, as trustee of a trust that holds a greater-than-25% voting interest in American Century Companies, Inc. (“ACC”). Under the Investment Company Act of 1940, this interest is presumed to represent control of ACC even though it is less than a majority interest. Because ACC is the parent corporation of the funds' advisors, the change of trustee is considered a technical assignment of the funds' management and subadvisory agreements.  Under the 1940 Act, this assignment automatically terminated the agreements.  Shareholders are being asked to approve new agreements that are substantially identical to the terminated agreements. This will not result in changes in the management of Americ an Century Investments, the funds, their investment objectives, advisory fees or services provided.

·   Amending the Articles of Incorporation for the following fund issuers: American Century Capital Portfolios, Inc., American Century Mutual Funds, Inc. and American Century World Mutual Funds, Inc.

This proposal is intended to achieve consistency among all fund issuers organized as Maryland corporations. The law of Maryland permits corporations to provide directors with some protection from personal liability.

You can vote today using the control number and phone number or Web site address shown on your vote card.

If you have any questions or to vote your shares, please contact our proxy solicitation agent, Broadridge Financial Solutions, Inc., toll-free at 1-866-450-8467. Representatives are available weekdays 9:30 a.m. to 9:00 p.m. and Saturdays from 10:00 a.m. to 6:00 p.m. Eastern time.

Please remember, the Board has unanimously recommended a vote “FOR” the proposal(s) detailed in your proxy statement.