Affiliated Managers (MGR) 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.     )
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AFFILIATED MANAGERS GROUP, INC.
(Name of Registrant as Specified In Its Charter)
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*** Exercise Your Right to Vote *** Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to Be Held on June 18, 2012. Meeting Information AFFILIATED MANAGERS GROUP, INC. Meeting Type: Annual Meeting For holders as of: April 20, 2012 Date: June 18, 2012 Time: 10:00 AM ET Location: Affiliated Managers Group, Inc. 600 Hale Street Prides Crossing, MA 01965 You are receiving this communication because you hold shares in the above named company. This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side). We encourage you to access and review all of the important information contained in the proxy materials before voting. AFFILIATED MANAGERS GROUP, INC. 600 HALE STREET PRIDES CROSSING, MA 01965 M45575-P25400 See the reverse side of this notice to obtain proxy materials and voting instructions.

Before You Vote How to Access the Proxy Materials Proxy Materials Available to VIEW or RECEIVE:  NOTICE AND PROXY STATEMENT FORM 10-K How to View Online: Have the information that is printed in the box marked by the arrow (located on the following page) and visit: www.proxyvote.com. How to Request and Receive a PAPER or E-MAIL Copy: If you want to receive a paper or e-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request: 1) BY INTERNET: www.proxyvote.com 2) BY TELEPHONE: 1-800-579-1639 3) BY E-MAIL*: sendmaterial@proxyvote.com * If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow (located on the following page) in the subject line. XXXX XXXX XXXX XXXX XXXX XXXX Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before May 21, 2012 to facilitate timely delivery. M45576-P25400 How To Vote Please Choose One of the Following Voting Methods Vote In Person: Many shareholder meetings have attendance requirements. Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares. Vote By Internet: To vote now by Internet, go to www.proxyvote.com. Have the information that is printed in the box marked by the arrow available and follow the instructions. Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card. XXXX XXXX XXXX

Voting Items The Board of Directors recommends you vote FOR the following proposals: 1. Election of Directors Nominees: a. Samuel T. Byrne b. Dwight D. Churchill c. Sean M. Healey d. Harold J. Meyerman e. William J. Nutt f. Tracy P. Palandjian g. Rita M. Rodriguez h. Patrick T. Ryan i. Jide J. Zeitlin 2. To approve, by a non-binding advisory vote, the compensation of the Company's named executive officers. 3. To ratify the selection of PricewaterhouseCoopers LLP as the Company's independent registered public accounting firm for the current fiscal year. M45577-P25400 NOTE: Such other business as may properly come before the meeting or any adjournment thereof.

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