[Form 4] Brookline Bancorp Inc Insider Trading Activity

Rhea-AI Filing Summary

Mark J. Meiklejohn, Chief Credit Officer and director of Brookline Bancorp, Inc. (BRKL), reported multiple dispositions of company common stock on 08/25/2025. The Form 4 shows four separate dispositions totaling 10,939 shares sold at $11.03 per share. After these transactions the reporting person beneficially owned 101,003 shares. The filing explains these were performance-based restricted stock shares that vested under the company’s 2021 Stock Option and Incentive Plan and pursuant to the Agreement and Plan of Merger among Berkshire Hills Bancorp, Commerce Acquisition Sub and Brookline Bancorp. The Form 4 was signed by a power of attorney on 08/27/2025.

Positive

• Full disclosure provided: The Form 4 specifies the vesting source (performance-based restricted stock) and links to the merger agreement and the 2021 incentive plan.
• Insider retains significant holdings: After dispositions the reporting person still beneficially owns 101,003 shares.

Negative

• None.

Insights

Securities Analyst

TL;DR: Insider disposed of 10,939 vested performance shares at $11.03, leaving 101,003 shares; tied to merger vesting.

The transaction reflects post-vesting dispositions rather than open-market opportunistic sales tied to compensation vesting from the merger agreement. The quantity (10,939 shares) relative to the final beneficial ownership (101,003 shares) indicates the insider remains a significant holder. Because the filing explicitly attributes the shares to performance-based restricted awards that vested under the merger agreement, this reduces interpretation risk that the sales signal firm-specific negative information. Materiality to shareholders depends on company float and market context, which are not provided in this Form 4.

Corporate Governance Expert

TL;DR: Dispositions were vesting-driven under merger terms; governance disclosure appears standard and complete.

The Form 4 discloses the nature of the shares (performance-based restricted stock) and links vesting to the merger agreement and the company’s 2021 incentive plan, satisfying typical disclosure expectations for Rule 16 reporting. The report is signed by a permitted power of attorney. No indications of unusual trading timing or omissions are visible from the filing text alone. Further assessment of governance impact would require broader context on the merger terms and overall insider ownership trends.

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^*

Meiklejohn Mark J.

(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)
	Chief Credit Officer

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		3,175(1)	D	$11.03	108,767	D
Common	08/25/2025		F		1,582	D	$11.03	107,185	D
Common	08/25/2025		F		3,510	D	$11.03	103,675	D
Common	08/25/2025		F		2,672	D	$11.03	101,003	D
Common								101,003	D

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:

	Mark J. Meiklejohn, 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did Mark J. Meiklejohn report on the Form 4 for BRKL?

He reported four dispositions on 08/25/2025 totaling 10,939 shares sold at $11.03 per share, leaving 101,003 shares beneficially owned.

Why were the shares disposed according to the filing?

The filing explains the shares were performance-based restricted stock that vested pursuant to the Brookline Bancorp 2021 Stock Option and Incentive Plan and the Agreement and Plan of Merger.

When was the Form 4 signed and by whom?

The Form 4 was signed by a power of attorney, Marissa S. Martin, on behalf of Mark J. Meiklejohn on 08/27/2025.

What roles does the reporting person hold at BRKL?

The reporting person is listed as a Director and the company’s Chief Credit Officer.

How many separate disposition transactions are reported?

There are four separate disposition line items reported on 08/25/2025.