[Form 4] Brookline Bancorp Inc Insider Trading Activity

Rhea-AI Filing Summary

Carl M. Carlson, Co-President & CFO of Brookline Bancorp, Inc. (BRKL), reported multiple dispositions of common stock on 08/25/2025. The filing shows four separate disposals at a price of $11.03 per share, reducing Mr. Carlson's direct beneficial ownership from 167,196 shares to 156,695 shares — a net decline of 10,501 shares. The form also reports an indirect holding of 1,033 shares held through an ESOP. The transactions are described as performance-based restricted stock that vested under the companys 2021 Stock Option and Incentive Plan and in connection with the Agreement and Plan of Merger.

Positive

• Significant retained ownership: After the transactions, Mr. Carlson still directly holds 156,695 shares and indirectly holds 1,033 shares via an ESOP.
• Disclosure clarity: The Form 4 explains the disposals arose from vesting of performance-based restricted stock under the 2021 Incentive Plan and the merger agreement.

Negative

• Insider dispositions: Mr. Carlson disposed of a net 10,501 shares on 08/25/2025 at $11.03 per share, reducing his direct stake.
• Concentration risk: A large executive holding can amplify perceived insider selling when any disposals occur, even if modest in size.

Insights

Securities Analyst

TL;DR: Insider sold a modest block of vested performance shares, leaving a substantial remaining stake.

The reported disposals total 10,501 common shares at $11.03 per share on 08/25/2025, arising from the vesting of performance-based restricted stock under the 2021 Incentive Plan and the merger agreement. While disposals reduce direct ownership, Mr. Carlson retains 156,695 direct shares plus 1,033 indirect ESOP shares, indicating continued alignment with shareholders. The transactions appear administrative following vesting rather than opportunistic trading, and the dollar amount is relatively small for a public company insider.

Corporate Governance Expert

TL;DR: Dispositions reflect vested awards related to a merger; governance disclosure is compliant and routine.

The Form 4 discloses multiple "F" code dispositions tied to vested performance restricted stock under the companys equity plan and the merger agreement. The filing includes a power-of-attorney signature and clear explanation of the vesting source. From a governance perspective, the report is timely and provides necessary detail for investor oversight. The retained ownership remains material, supporting continued executive stake in the company.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Carlson Carl M

(Last) (First) (Middle)

131 CLARENDON STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
BROOKLINE BANCORP INC [ BRKL ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Co-President & CFO

3. Date of Earliest Transaction (Month/Day/Year)
08/25/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common	08/25/2025		F		3,908(1)	D	$11.03	167,196	D
Common	08/25/2025		F		1,969	D	$11.03	165,227	D
Common	08/25/2025		F		4,320	D	$11.03	160,907	D
Common	08/25/2025		F		4,212	D	$11.03	156,695	D
Common								156,695	D
Common								1,033	I	By ESOP

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Performance based restricted stock shares granted pursuant to the Brookline Bancorp, Inc. 2021 Stock Option and Incentive Plan. The shares vested pursuant to the terms of the Agreement and Plan of Merger by and among Berkshire Hills Bancorp, Inc., Commerce Acquisition Sub, Inc., and Brookline Bancorp, Inc.

Remarks:

	Carl M. Carlson, by Marissa S. Martin, P.O.A.	08/27/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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FAQ

What did BRKL insider Carl M. Carlson report on Form 4?

The filing reports multiple dispositions of common stock on 08/25/2025 tied to vested performance-based restricted shares; total direct holdings after the transactions are 156,695 shares.

How many shares did Carl M. Carlson sell and at what price?

Mr. Carlson disposed of a net 10,501 shares across reported transactions on 08/25/2025 at a price of $11.03 per share.

Why were the shares disposed of according to the Form 4?

The Explanation states the shares were performance-based restricted stock that vested under the Brookline Bancorp, Inc. 2021 Stock Option and Incentive Plan and the Agreement and Plan of Merger.

Does Carl M. Carlson still hold shares in BRKL after these transactions?

Yes. After the reported dispositions his direct beneficial ownership is 156,695 shares and he has an indirect holding of 1,033 shares via an ESOP.

When was the Form 4 signed and by whom?

The signature block shows Carl M. Carlson, by Marissa S. Martin, P.O.A. with a signature date of 08/27/2025 on the form.