SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* Horgen Jay C. (Last) (First) (Middle) C/O AFFILIATED MANAGERS GROUP, INC. 600 HALE STREET (Street) PRIDES CROSSING MA 01965 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 04/22/2008	3. Issuer Name and Ticker or Trading Symbol AFFILIATED MANAGERS GROUP INC [ AMG ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner X Officer (give title below) Other (specify below) Executive Vice President	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	5,216(1)	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (Right to Buy)	03/05/2010(2)	03/05/2014	Common Stock	60,000	105.44	D
Employee Stock Option (Right to Buy)	12/31/2012(3)	12/20/2014	Common Stock	93,318	116.35	D

Explanation of Responses:

1. Mr. Horgen was granted a discretionary award under the Company's Deferred Compensation Plan, which award is invested at the election of Mr. Horgen in common stock of the Company, distributable in 25% increments in each of the years 2009, 2010, 2011 and 2012.

2. This option is exercisable over three years, with 33.3% exercisable beginning on each of March 5, 2008, 2009 and 2010. The exercisability of the option would be accelerated upon a change of control of the Company.

3. This option is exerciable over five years, with 22.5% exercisable beginning on each of December 31, 2008, 2009, 2010 and 2011 and 10% exercisable on December 31, 2012. The exercisability of the option would be accelerated upon a change of control of the Company.

	/s/ John Kingston, III, Attorney-in-Fact	04/23/2008
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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EXHIBIT 24
POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned
hereby severally constitutes and appoints John
Kingston, III, Darrell W. Crate and Nathaniel Dalton,
and each of them singly, with full power of
substitution and resubstitution, as the undersigned's
true and lawful attorney-in-fact with full power and
authority to them, and each of them singly, to
prepare, sign and file for the undersigned, in the
undersigned's name and capacity indicated below, any
and all filings and documents (including without
limitation any exhibits and amendments thereto) of the
undersigned or Affiliated Managers Group, Inc.
pursuant to the Securities Exchange Act of 1934, as
amended (the "Act"), including without limitation
filings pursuant to Section 16 of the Act and the
rules and regulations promulgated thereunder, and
generally to do all such things in the undersigned's
name and capacity indicated below to enable the
undersigned and Affiliated Managers Group, Inc. to
comply with the provisions of the Act and all
requirements of the Securities and Exchange
Commission, hereby ratifying and confirming the
undersigned's signatures as they may be signed by said
attorneys, or any of them, or any substitute or
substitutes of any of them, on said filings,
documents, exhibits and any and all amendments
thereto, and hereby ratifying and confirming all that
said attorneys, or any of them, or any substitute or
substitutes of any of them, may lawfully do or cause
to be done by virtue hereof.

Witness my hand, this 22nd day of April, 2008.


By:	/s/ Jay c. Horgen
Name:	Jay C. Horgen
Title:	Executive Vice President