[Form 4] Brookline Bancorp Inc Insider Trading Activity

Rhea-AI Filing Summary

William C. Tsonos, identified as a director and officer (CEO, Bank Rhode Island) of Brookline Bancorp, reported a transaction dated 09/01/2025 that disposed of 38,017 shares of Brookline common stock with 0 shares owned following the transaction. The filing explains this disposition resulted from an Agreement and Plan of Merger under which each Brookline share was converted into the right to receive 0.42 shares of Berkshire Hills Bancorp, Inc. common stock, with cash paid in lieu of any fractional share. The Form 4 was signed under power of attorney on 09/02/2025.

Positive

• Transaction transparently disclosed as Form 4 filing showing the exact number of shares disposed (38,017) and post-transaction ownership (0).
• Disposition resulted from a merger conversion, indicating the change was a corporate action rather than an undisclosed private sale.

Negative

• Reporting person holds no Brookline shares after conversion, eliminating direct insider ownership in the predecessor equity.
• Form 4 shows a material ownership change tied to the merger, which may reduce direct alignment with former Brookline shareholders.

Insights

Securities Analyst

TL;DR: Insider ownership in BRKL was eliminated due to a merger conversion into Berkshire Hills shares and cash.

The Form 4 documents a non-derivative disposition of 38,017 Brookline shares on 09/01/2025, leaving the reporting person with zero Brookline shares thereafter. The filer is identified as a director and an officer (CEO, Bank Rhode Island), which makes the change relevant for disclosure and ownership tracking. The disposition is described as occurring pursuant to a merger agreement converting Brookline stock into 0.42 shares of Berkshire Hills common stock plus cash for fractions. For investors and compliance teams, this is a clean structural change in beneficial ownership tied to corporate action rather than a voluntary open-market sale.

Corporate Governance Expert

TL;DR: Transaction stems from a corporate merger, not an independent transaction by the insider.

The filing indicates the change in beneficial ownership resulted from the terms of the Agreement and Plan of Merger, which is a material corporate event that automatically converts securities. The reporting person’s status as director and officer increases the importance of clear disclosure; the Form 4 appropriately reports disposal and post-transaction ownership of zero. This does not by itself indicate misconduct or discretionary insider trading, but it materially alters the insider’s direct stake in the predecessor company due to the merger consideration.

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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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^*

Tsonos William C

(Last) (First) (Middle)

131 CLARENDON STREET

(Street)

BOSTON MA 02117

(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)
	CEO Bank Rhode Island

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		38,017	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:

	William C. Tsonos, by Marissa S. Martin, POA	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

Who filed the Form 4 for BRKL and what is their role?

The Form 4 was filed for William C. Tsonos, identified as a director and an officer (CEO, Bank Rhode Island) of Brookline Bancorp.

What transaction is reported on the BRKL Form 4 dated 09/01/2025?

The filing reports a disposition of 38,017 shares of Brookline common stock on 09/01/2025, leaving 0 shares beneficially owned.

Why were the Brookline shares disposed according to the filing?

The shares were converted pursuant to an Agreement and Plan of Merger, where each Brookline share was converted into 0.42 shares of Berkshire Hills Bancorp common stock plus cash for fractional shares.

When was the Form 4 signed and by whom?

The Form 4 was signed under power of attorney by Marissa S. Martin on behalf of William C. Tsonos on 09/02/2025.

Does the Form 4 indicate any derivative holdings or other securities?

No. Table II for derivative securities contains no reported entries; only non-derivative common shares are reported in Table I.