UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No. 1)*
Affiliated Managers Group, Inc.
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(Name of Issuer)
Common Stock
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(Title of Class of Securities)
008252108
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(CUSIP Number)
December 31, 2002
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(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to
designate the rule pursuant to which this Schedule is filed:
[x] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[ ] Rule 13d-1(d)
*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).
SEC 1745 (2/92)
Page 1 of 9 pages
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CUSIP No. 008252108 13G Page 2 of 9 pages
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1 NAME OF REPORTING PERSON
S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Liberty Wanger Asset Management, L.P. 36-3820584
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2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
Not Applicable (a) [ ]
(b) [ ]
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3 SEC USE ONLY
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4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
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NUMBER OF 5 SOLE VOTING POWER
SHARES None
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BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY 857,000
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EACH 7 SOLE DISPOSITIVE POWER
REPORTING None
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PERSON 8 SHARED DISPOSITIVE POWER
WITH 857,000
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9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
857,000
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10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
Not Applicable
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11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
3.9%
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12 TYPE OF REPORTING PERSON*
IA
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*SEE INSTRUCTION BEFORE FILLING OUT!
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CUSIP No. 008252108 13G Page 3 of 9 pages
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1 NAME OF REPORTING PERSON
S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
WAM Acquisition GP, Inc.
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2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
Not Applicable (a) [ ]
(b) [ ]
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3 SEC USE ONLY
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4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
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NUMBER OF 5 SOLE VOTING POWER
SHARES None
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BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY 857,000
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EACH 7 SOLE DISPOSITIVE POWER
REPORTING None
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PERSON 8 SHARED DISPOSITIVE POWER
WITH 857,000
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9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
857,000
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10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
Not Applicable
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11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
3.9%
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12 TYPE OF REPORTING PERSON*
CO
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*SEE INSTRUCTION BEFORE FILLING OUT!
Item 1(a) Name of Issuer:
Affiliated Managers Group, Inc.
Item 1(b) Address of Issuer's Principal Executive Offices:
600 Hale Street
Prides Crossing, Massachusetts 01965
Item 2(a) Name of Person Filing:
Liberty Wanger Asset Management, L.P. ("WAM")
WAM Acquisition GP, Inc., the general partner of WAM
("WAM GP")
Item 2(b) Address of Principal Business Office:
WAM and WAM GP are all located at:
227 West Monroe Street, Suite 3000
Chicago, Illinois 60606
Item 2(c) Citizenship:
WAM is a Delaware limited partnership; and WAM GP is a
Delaware corporation.
Item 2(d) Title of Class of Securities:
Common Stock
Item 2(e) CUSIP Number:
008252108
Item 3 Type of Person:
(e) WAM is an Investment Adviser registered under
section 203 of the Investment Advisers Act of
1940; WAM GP is the General Partner of the
Investment Adviser.
Page 4 of 9 Pages
Item 4 Ownership (at December 31, 2002):
(a) Amount owned "beneficially" within the meaning of
rule 13d-3:
857,000
(b) Percent of class:
3.9% (based on 21,754,520 shares outstanding as
of November 11, 2002, reported in Form 10-Q filed
on November 14, 2002).
(c) Number of shares as to which such person has:
(i) sole power to vote or to direct the
vote: none
(ii) shared power to vote or to direct the
vote: 857,000
(iii) sole power to dispose or to direct the
disposition of: none
(iv) shared power to dispose or to direct
disposition of: 857,000
Item 5 Ownership of Five Percent or Less of a Class:
If this statement is being filed to report the fact that
as of the date hereof the reporting person has ceased to
be the beneficial owner of more than five percent of the
class of securities, check the following: [x]
Item 6 Ownership of More than Five Percent on Behalf of Another
Person:
Not Applicable
Item 7 Identification and Classification of the Subsidiary Which
Acquired the Security Being Reported on by the Parent Holding
Company:
Not Applicable
Item 8 Identification and Classification of Members of the Group:
Not Applicable
Item 9 Notice of Dissolution of Group:
Not Applicable
Page 5 of 9 Pages
Item 10 Certification:
By signing below I certify that, to the best of my
knowledge and belief, the securities referred to above were
acquired and are held in the ordinary course of business and
were not acquired and are not held for the purpose of or with
the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not
held in connection with or as a participant in any transaction
having that purpose or effect.
Page 6 of 9 Pages
Signature
After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.
Date: February 13, 2003
The undersigned corporation, on the date above written, agrees
and consents to the joint filing on its behalf of this
Schedule 13G in connection with its beneficial ownership of
the security reported herein.
WAM Acquisition GP, Inc.
for itself and as general partner of
LIBERTY WANGER ASSET MANAGEMENT, L.P.
By: /s/ Bruce H. Lauer
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Bruce H. Lauer
Senior Vice President and Secretary
Page 7 of 9 Pages
Exhibit Index
Exhibit 1 Joint Filing Agreement dated as of February 13, 2003 by and
among Liberty Wanger Asset Management, L.P. and WAM
Acquisition GP, Inc.
Page 8 of 9 Pages