Boston Partners (MBC) cuts MasterBrand holdings to zero in latest 13G/A

Rhea-AI Filing Summary

MasterBrand, Inc. received an amended Schedule 13G/A (Amendment No. 3) from Boston Partners regarding its holdings of MasterBrand common stock. Boston Partners reports that it now beneficially owns 0 shares, representing 0% of the class, with no sole or shared voting or dispositive power over any shares. The filer indicates it now holds ownership of 5 percent or less of this class of securities.

Key Figures

Beneficial ownership: 0 shares Percent of class: 0% Sole voting power: 0 shares +3 more

6 metrics

Beneficial ownership 0 shares Shares of MasterBrand common stock beneficially owned by Boston Partners

Percent of class 0% Percentage of MasterBrand common stock class owned by Boston Partners

Sole voting power 0 shares Shares over which Boston Partners has sole power to vote

Shared voting power 0 shares Shares over which Boston Partners has shared power to vote

Sole dispositive power 0 shares Shares over which Boston Partners has sole dispositive power

Shared dispositive power 0 shares Shares over which Boston Partners has shared dispositive power

Key Terms

beneficially owned, Sole Voting Power, Shared Dispositive Power, Ownership of 5 percent or less of a class

4 terms

beneficially owned financial

"Amount beneficially owned: 0"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

Sole Voting Power financial

"Sole power to vote or to direct the vote: Boston Partners - 0"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

Shared Dispositive Power financial

"Shared power to dispose or to direct the disposition of: Boston Partners - 0"

Ownership of 5 percent or less of a class regulatory

"Item 5. | Ownership of 5 Percent or Less of a Class."

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/04/2026 - 01:39 PM Accepted by SEC EDGAR 08/04/2026 - 01:39 PM Learn about SEC filing dates

FAQ

What did Boston Partners report in its Schedule 13G/A for MasterBrand (MBC)?

Boston Partners reported it now beneficially owns 0 shares of MasterBrand common stock, representing 0% of the class, with no sole or shared voting or dispositive power over any shares.

Does Boston Partners still hold a significant stake in MasterBrand (MBC)?

No. Boston Partners reported ownership of 0% of MasterBrand’s common stock and confirmed it holds 5 percent or less of the class, indicating it no longer has a significant reportable stake.

How many MasterBrand (MBC) shares does Boston Partners beneficially own?

Boston Partners reported that it beneficially owns 0 shares of MasterBrand common stock, with no sole or shared voting power and no sole or shared dispositive power over any shares.

What voting power over MasterBrand (MBC) shares does Boston Partners report?

Boston Partners reports 0 shares with sole voting power and 0 shares with shared voting power, meaning it has no voting authority over any MasterBrand common stock.

Who signed the Schedule 13G/A for MasterBrand (MBC) on behalf of Boston Partners?

The filing was signed by Ali Farooqi, Senior Compliance Manager at Boston Partners, who executed the certification for the amended beneficial ownership report.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 3)

MasterBrand, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

57638P104

(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): 57638P104

1

Names of Reporting Persons

Boston Partners

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 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

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)

0 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MasterBrand, Inc.
(b)	Address of issuer's principal executive offices: 3300 ENTERPRISE PARKWAY, SUITE 300, BEACHWOOD, OHIO 44122
Item 2.
(a)	Name of person filing: Boston Partners
(b)	Address or principal business office or, if none, residence: ONE BEACON STREET 30TH FLOOR BOSTON, Massachusetts 02108
(c)	Citizenship: Boston Partners - DELAWARE
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 57638P104
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: 0
(b)	Percent of class: 0 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Boston Partners - 0
	(ii) Shared power to vote or to direct the vote: Boston Partners - 0
	(iii) Sole power to dispose or to direct the disposition of: Boston Partners - 0
	(iv) Shared power to dispose or to direct the disposition of: Boston Partners - 0
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.
	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.

Boston Partners

Signature:	/s/ Ali Farooqi
Name/Title:	Ali Farooqi / Senior Compliance Manager
Date:	08/04/2026