Affiliated Managers (MGR) S-3ASR Automatic shelf registration

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Exhibit 5.2

RICHARDS, LAYTON & FINGER
A PROFESSIONAL ASSOCIATION
ONE RODNEY SQUARE
920 NORTH KING STREET
WILMINGTON, DELAWARE 19801
(302) 651-7700
FAX: (302) 651-7701
WWW.RLF.COM

        December 12, 2007

Affiliated Managers Group, Inc.
600 Hale Street
Prides Crossing, MA 01965

Re:

AMG Capital Trust II

Ladies and Gentlemen:

        We have acted as special Delaware counsel for AMG Capital Trust II, a Delaware statutory trust (the "Trust"), in connection with the matters set forth herein. At your request, this opinion is being furnished to you.

        We have examined and relied upon such records, documents, certificates and other instruments as in our judgment are necessary or appropriate to enable us to render the opinions expressed below, including the following documents:

(a)

The Certificate of Trust of the Trust (the "Certificate of Trust"), as filed with the office of the Secretary of State of the State of Delaware (the "Secretary of State") on October 11, 2007;



(b)

The Declaration of Trust, dated as of October 11, 2007, between the Affiliated Managers Group, Inc. (the "Company") and LaSalle National Trust Delaware, as Delaware trustee, as amended and restated by the Amended and Restated Declaration of Trust of the Trust, dated as of October 17, 2007, by the Company, the trustees of the Trust named therein, and the holders, from time to time, of undivided beneficial interests in the assets of the Trust (the "Trust Agreement");



(c)

The Registration Statement (the "Registration Statement") on Form S-3, including a prospectus (the "Prospectus") relating to the 5.15% convertible trust preferred securities of the Trust representing beneficial interests in the assets of the Trust (each, a "Trust Preferred Security" and collectively, the "Trust Preferred Securities"), to be filed by the Company and the Trust with the Securities and Exchange Commission on or about December 12, 2007;



(d)

The Purchase Agreement;



(e)

The Offering Memorandum; and



(f)

A Certificate of Good Standing for the Trust, dated December 12, 2007, obtained from the Secretary of State.

        Initially capitalized terms used herein and not otherwise defined are used as defined in the Trust Agreement.

        As to various questions of fact material to our opinion, we have relied upon the representations made in the foregoing documents and upon certificates of officers of the Company.

        With respect to all documents examined by us, we have assumed (i) the authenticity of all documents submitted to us as originals, (ii) the conformity with the originals of all documents submitted to us as copies or forms, and (iii) the genuineness of all signatures.

        For purposes of this opinion, we have assumed (i) that the Trust Agreement and the Certificate of Trust will be in full force and effect and will not be amended, (ii) the due organization or due formation, as the case may be, and valid existence in good standing of each party to the documents (other than the Trust) examined by us under the laws of the jurisdiction governing its organization or formation, (iii) the legal capacity of natural persons who are signatories to the documents examined by us, (iv) that each of the parties to the documents (other than the

Trust) examined by us has the power and authority to execute and deliver, and to perform its obligations under, such documents, (v) the due authorization, execution and delivery by all parties thereto of all documents (other than the Trust) examined by us, (vi) the receipt by each Person to whom a Trust Preferred Security was issued by the Trust (collectively, the "Trust Preferred Security Holders") of a Trust Preferred Security Certificate for such Trust Preferred Security and the payment for such Trust Preferred Security, in accordance with the Trust Agreement, the Purchase Agreement and the Offering Memorandum, and (vii) that the Trust Preferred Securities were authenticated, issued and sold to the Trust Preferred Security Holders in accordance with the Trust Agreement, the Purchase Agreement and the Offering Memorandum. We have not participated in the preparation of the Offering Memorandum, the Registration Statement (except for providing this opinion) or the Prospectus and assume no responsibility for their contents, other than this opinion.

        This opinion is limited to the laws of the State of Delaware (excluding the securities laws of the State of Delaware), and we have not considered and express no opinion on the laws of any other jurisdiction, including federal laws and rules and regulations relating thereto. Our opinions are rendered only with respect to Delaware laws and rules, regulations and orders thereunder which are currently in effect.

        Based upon the foregoing, and upon our examination of such questions of laws and rules, regulations and orders thereunder as we have considered necessary or appropriate, and subject to the assumptions, qualifications, limitations and exceptions set forth herein, we are of the opinion that:

1.

The Trust has been duly formed and is validly existing in good standing as a statutory trust under the Statutory Trust Act.



2.

The Trust Preferred Securities of the Trust have been duly authorized by the Trust Agreement, have been duly and validly issued and, subject to the qualifications set forth in paragraph 3 below, are fully paid and nonassessable undivided beneficial interests in the assets of the Trust.



3.

The Trust Preferred Security Holders, as beneficial owners of the Trust, are entitled to the same limitation of personal liability extended to stockholders of private corporations for profit organized under the General Corporation Law of the State of Delaware. We note that the Trust Preferred Security Holders may be obligated to make payments as set forth in the Trust Agreement.

        We consent to the filing of this opinion with the Securities and Exchange Commission as an exhibit to the Registration Statement. We hereby consent to the use of our name under the heading "Validity of Securities" in the Prospectus. In giving the foregoing consents, we do not thereby admit that we come within the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended, or the rules and regulations of the Securities and Exchange Commission thereunder.

Very truly yours,

/s/ RICHARDS, LAYTON & FINGER, P.A.

Richards, Layton & Finger, P.A.

EAM/JWP/AWR

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Exhibit 5.2