Affiliated Managers Group (AMG): Morgan Stanley, Atlanta Capital detail 5.5% and 4.7% stakes

Rhea-AI Filing Summary

Morgan Stanley and Atlanta Capital Management Company, LLC report their ownership in Affiliated Managers Group, Inc. common stock on an amended Schedule 13G. As of June 30, 2026, Morgan Stanley, through certain reporting units, is deemed to beneficially own 1,458,379 shares, representing 5.5% of the common stock, with 1,271,033 shares of shared voting power and 1,390,098 shares of shared dispositive power. Atlanta Capital reports 1,238,446 shares, or 4.7%, with shared voting power over 1,070,189 shares and shared dispositive power over 1,175,026 shares, and states it has ceased to be the beneficial owner of more than five percent of the class.

Key Figures

Morgan Stanley beneficial ownership: 1,458,379 shares Morgan Stanley percent of class: 5.5 % Morgan Stanley shared voting power: 1,271,033 shares +5 more

8 metrics

Morgan Stanley beneficial ownership 1,458,379 shares Affiliated Managers Group common stock, representing 5.5% of the class as of June 30, 2026

Morgan Stanley percent of class 5.5 % Affiliated Managers Group common stock beneficial ownership

Morgan Stanley shared voting power 1,271,033 shares Affiliated Managers Group common stock with shared voting power

Morgan Stanley shared dispositive power 1,390,098 shares Affiliated Managers Group common stock with shared dispositive power

Atlanta Capital beneficial ownership 1,238,446 shares Affiliated Managers Group common stock, representing 4.7% of the class as of June 30, 2026

Atlanta Capital percent of class 4.7 % Affiliated Managers Group common stock beneficial ownership, below 5% threshold

Atlanta Capital shared voting power 1,070,189 shares Affiliated Managers Group common stock with shared voting power

Atlanta Capital shared dispositive power 1,175,026 shares Affiliated Managers Group common stock with shared dispositive power

Key Terms

beneficial owner, shared voting power, shared dispositive power, parent holding company, +1 more

5 terms

beneficial owner financial

"has ceased to be the beneficial owner of more than five percent"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

shared voting power financial

"Shared Voting Power 1,271,033.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

shared dispositive power financial

"Shared Dispositive Power 1,390,098.00"

parent holding company financial

"If a parent holding company has filed this schedule"

Schedule 13G regulatory

"this filing reflects the securities beneficially owned ... of Morgan Stanley"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

FAQ

What ownership stake in AMG does Morgan Stanley report on this Schedule 13G/A?

Morgan Stanley reports beneficial ownership of 1,458,379 AMG common shares, representing 5.5% of the class, with shared voting power over 1,271,033 shares and shared dispositive power over 1,390,098 shares as of June 30, 2026.

How many AMG shares does Atlanta Capital Management Company, LLC report owning?

Atlanta Capital reports beneficial ownership of 1,238,446 AMG common shares, representing 4.7% of the class, with shared voting power over 1,070,189 shares and shared dispositive power over 1,175,026 shares as of June 30, 2026.

Has Atlanta Capital remained a more-than-5% beneficial owner of AMG (symbol AMG)?

No. Atlanta Capital states that, as of the reporting date, it has ceased to be the beneficial owner of more than five percent of AMG’s common stock, and now reports a 4.7% ownership position.

What percentage of AMG’s common stock is reported as owned by Morgan Stanley?

Morgan Stanley reports a 5.5% beneficial ownership of AMG’s common stock, corresponding to 1,458,379 shares, held through certain reporting units with shared voting and dispositive powers identified in the Schedule 13G/A.

Do Morgan Stanley and Atlanta Capital report sole or shared voting power over AMG shares?

Both report zero sole voting and dispositive power. Morgan Stanley reports 1,271,033 shares of shared voting power and 1,390,098 of shared dispositive power, while Atlanta Capital reports 1,070,189 and 1,175,026 shares, respectively.

Who signed the joint AMG ownership filing on behalf of Morgan Stanley and Atlanta Capital?

The filing is signed by Claire Gordon, Authorized Signatory for Morgan Stanley, and Kelly Williams, Authorized Signatory for Atlanta Capital Management Company, LLC, each signing on August 12, 2026 under a joint filing agreement.

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Available on EDGAR 08/12/2026 - 02:53 PM Accepted by SEC EDGAR 08/12/2026 - 02:52 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 7)

AFFILIATED MANAGERS GROUP, INC.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

008252108

(CUSIP Number)

06/30/2026

(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)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 008252108

1

Names of Reporting Persons

Morgan Stanley

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,271,033.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,390,098.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,458,379.00

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)

5.5 %

12

Type of Reporting Person (See Instructions)

HC, CO

SCHEDULE 13G

CUSIP Number(s): 008252108

1

Names of Reporting Persons

Atlanta Capital Management Company, LLC

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,070,189.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,175,026.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,238,446.00

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)

4.7 %

12

Type of Reporting Person (See Instructions)

IA, CO

Comment for Type of Reporting Person: As of the date hereof, Atlanta Capital Management Company, LLC has ceased to be the beneficial owner of more than five percent of the class of securities.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: AFFILIATED MANAGERS GROUP, INC.
(b)	Address of issuer's principal executive offices: 1001 U.S. HIGHWAY ONE NORTH, SUITE 702, JUPITER, FL, 33477
Item 2.
(a)	Name of person filing: 1: Morgan Stanley 2: Atlanta Capital Management Company, LLC
(b)	Address or principal business office or, if none, residence: 1: 1585 Broadway, New York, NY 10036 ;2: 1075 Peachtree Street, Suite 2100, Atlanta, GA 30309
(c)	Citizenship: 1: Delaware 2: Delaware
(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: See the response(s) to Item 9 on the attached cover page(s).
(b)	Percent of class: 5.5 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See the response(s) to Item 5 on the attached cover page(s).
	(ii) Shared power to vote or to direct the vote: See the response(s) to Item 6 on the attached cover page(s).
	(iii) Sole power to dispose or to direct the disposition of: See the response(s) to Item 7 on the attached cover page(s).
	(iv) Shared power to dispose or to direct the disposition of: See the response(s) to Item 8 on the attached cover page(s).
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 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 or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See Exhibit 99.2
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. * In Accordance with the Securities and Exchange Commission Release No. 34-39538 (January 12, 1998) (the "Release"), this filing reflects the securities beneficially owned, or that may be deemed to be beneficially owned, by certain operating units (collectively, the "MS Reporting Units") of Morgan Stanley and its subsidiaries and affiliates (collectively, "MS"). This filing does not reflect securities, if any, beneficially owned by any operating units of MS whose ownership of securities is disaggregated from that of the MS Reporting Units in accordance with the Release.

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.

Morgan Stanley

Signature:	Claire Gordon
Name/Title:	Authorized Signatory, Morgan Stanley
Date:	08/12/2026

Atlanta Capital Management Company, LLC

Signature:	Kelly Williams
Name/Title:	Authorized Signatory, Atlanta Capital Management Company, LLC
Date:	08/12/2026

Exhibit Information

EXHIBIT NO. EXHIBITS ------------------ ------------------------------------ 99.1 Joint Filing Agreement 99.2 Item 7 Information * Attention. Intentional misstatements or omissions of fact constitute federal criminal violations (see 18 U.S.C. 1001).