[SCHEDULE 13G/A] AFFILIATED MANAGERS GROUP, INC. SEC Filing

Rhea-AI Filing Summary

The Vanguard Group filed an amended Schedule 13G reporting passive ownership in Affiliated Managers Group (AMG). Vanguard beneficially owns 2,771,811 shares of AMG common stock, representing 9.75% of the class as of 09/30/2025.

The filing lists 0 shares with sole voting power and 174,684 with shared voting power. Vanguard reports 2,560,709 shares with sole dispositive power and 211,102 with shared dispositive power. Vanguard states the securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control. Clients of The Vanguard Group have rights to dividends or sale proceeds related to the reported securities, and no single client interest exceeds 5%.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 13)

Affiliated Managers Group Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

008252108

(CUSIP Number)

09/30/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 008252108

1

Names of Reporting Persons

The Vanguard Group

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 174,684.00
7	Sole Dispositive Power 2,560,709.00
8	Shared Dispositive Power 211,102.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,771,811.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

9.75 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Affiliated Managers Group Inc
(b)	Address of issuer's principal executive offices: 600 Hale Street, Prides Crossing, MA, 01965
Item 2.
(a)	Name of person filing: The Vanguard Group
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd., Malvern, PA 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 008252108
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 2771811
(b)	Percent of class: 9.75 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 174684
	(iii) Sole power to dispose or to direct the disposition of: 2560709
	(iv) Shared power to dispose or to direct the disposition of: 211102
Item 5.	Ownership of 5 Percent or Less of a Class.
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. The Vanguard Group, Inc.'s clients, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein. No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

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, other than activities solely in connection with a nomination under § 240.14a-11.

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.

The Vanguard Group

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	10/30/2025

FAQ

What stake in AMG did The Vanguard Group report?

Vanguard reported beneficial ownership of 2,771,811 shares of AMG, equal to 9.75% of the common stock.

What voting powers did Vanguard disclose for AMG (AMG)?

Vanguard reported 0 shares with sole voting power and 174,684 with shared voting power.

What dispositive powers did Vanguard report for AMG shares?

Vanguard has 2,560,709 shares with sole dispositive power and 211,102 with shared dispositive power.

Is Vanguard’s AMG filing passive or active?

The Schedule 13G/A is passive; Vanguard certified the holdings were acquired and held in the ordinary course, not to influence control.

When is the event date for Vanguard’s AMG ownership report?

The event date is 09/30/2025.

Do any Vanguard clients individually hold more than 5% of AMG?

No. The filing states no one other person's interest exceeds 5%.