[Form 4] Brookline Bancorp Inc Insider Trading Activity

Rhea-AI Filing Summary

Marissa S. Martin, listed as an officer (General Counsel) of Brookline Bancorp Inc. (BRKL), reported a transaction related to the companys merger on September 1, 2025. Under the merger agreement with Berkshire Hills Bancorp, each share of Brookline common stock converted into the right to receive 0.42 shares of Berkshire common stock, with cash paid for any fractional shares. The filing shows Ms. Martin disposed of 33,673 shares of Brookline common stock on that date and reports 0 shares owned after the transaction. The Form 4 was signed on September 2, 2025 and identifies the disposition as resulting from the merger conversion terms.

Positive

• Transaction disclosed promptly under Section 16, showing compliance with reporting rules
• Merger conversion terms are explicitly stated: each Brookline share converted into 0.42 Berkshire shares with cash for fractions

Negative

• Reporting person no longer holds Brookline common stock following the disposition (0 shares reported)
• Disposition of 33,673 shares reduces insider ownership in the issuer to zero

Insights

Securities Analyst

TL;DR: Insider disposition reflects share conversion under the Brookline-Berkshire merger; ownership reduced to zero.

The reported disposal is clearly tied to the merger mechanics converting Brookline shares into Berkshire shares and cash in lieu of fractions. This Form 4 records a non-derivative disposition of 33,673 shares, leaving the reporting officer with no direct ownership in Brookline post-transaction. For investors, this is a transactional disclosure rather than an independent trading signal since the disposition was effectuated by the merger consideration formula, not an open-market sale.

Corporate Governance Expert

TL;DR: The filing documents a routine, merger-driven change in insider holdings, disclosed in compliance with Section 16.

The form indicates appropriate disclosure timing and a signed certification by the reporting person. The nature of the transaction—conversion under the Agreement and Plan of Merger—is explicitly stated, which supports transparency around insider ownership changes linked to corporate control events. There is no indication of separate voluntary insider selling or unusual timing beyond the merger conversion date.

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

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X

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^*

Martin Marissa S.

(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)
	General Counsel

3. Date of Earliest Transaction (Month/Day/Year)
09/01/2025

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	09/01/2025		D		33,673	D	(1)	0	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. Pursuant to the terms of the Agreement and Plan of Merger by and among Berkshire Hills Bancorp, Inc. (Berkshire) , Commerce Acquisition Sub, Inc. and Brookline Bancorp, Inc. (the Issuer), on September 1, 2025, each share of Issuer common stock was converted into the right to receive 0.42 shares of Berkshire common stock and cash in lieu of any fractional share of Berkshire common stock.

Remarks:

	Marissa S. Martin	09/02/2025
	** 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 transaction did Marissa S. Martin report on Form 4 for BRKL?

She reported a disposition of 33,673 Brookline shares on 09/01/2025 resulting from the merger conversion.

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

The disposal occurred because under the Agreement and Plan of Merger each Brookline share was converted into 0.42 shares of Berkshire common stock with cash in lieu for fractional shares.

How many Brookline shares does the reporting person own after the reported transaction?

The Form 4 reports 0 shares beneficially owned following the reported transaction.

What is the reporting persons role at Brookline Bancorp?

The form identifies Marissa S. Martin as an Officer (General Counsel) of Brookline Bancorp.

When was the Form 4 signed and filed?

The signature block shows the form signed by Marissa S. Martin on 09/02/2025.