[Form 4] Brookline Bancorp Inc Insider Trading Activity

Rhea-AI Filing Summary

William C. Tsonos, identified as a director and CEO of Bank Rhode Island, reported multiple disposals of BROOKLINE BANCORP, INC. (BRKL) common shares on 08/25/2025 at a price of $11.03 per share. The transactions are coded F, reflecting dispositions tied to performance-based restricted stock that vested under the merger agreement among Berkshire Hills Bancorp, Commerce Acquisition Sub, and Brookline Bancorp. After the reported sales and vesting, Mr. Tsonos directly beneficially owns 38,017 shares and indirectly holds 1,191 shares through an ESOP. The Form 4 was signed via power of attorney.

Positive

• Disclosures clearly link the transactions to performance-based restricted stock vesting under a merger agreement
• Insider retains significant direct ownership (38,017 shares) after the reported transactions
• Indirect ESOP holdings remain (1,191 shares), indicating continued broader-plan alignment

Negative

• None.

Insights

Financial Analyst

TL;DR: Insider sold vested performance shares due to merger-related vesting; transaction was at $11.03 and leaves material direct ownership.

The reported disposals are the result of performance-based restricted stock vesting tied to a merger agreement, not a market-timed open-market sale. The per-share price of $11.03 is disclosed for each disposition line, and the aggregate post-transaction direct ownership of 38,017 shares indicates continued insider alignment with shareholders. Impact is limited because the movements reflect plan mechanics rather than discretionary liquidation, though the absolute share counts should be considered relative to outstanding shares when assessing voting influence.

Corporate Governance Expert

TL;DR: Vesting under a merger agreement triggered transfers; disclosure follows Section 16 reporting and indicates ongoing indirect ESOP holdings.

The Form 4 clearly attributes the changes to performance-based restricted stock vesting under the referenced merger agreement, which is typical in transaction consummations. The reporting person retains direct control of 38,017 shares and retains indirect ownership via an ESOP of 1,191 shares, preserving governance stakes. The use of a power of attorney for signature is procedural and disclosed. This filing raises no immediate governance red flags based on disclosed facts.

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
Estimated average burden
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^*

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)
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		2,615(1)	D	$11.03	43,707	D
Common	08/25/2025		F		872	D	$11.03	42,835	D
Common	08/25/2025		F		2,891	D	$11.03	39,944	D
Common	08/25/2025		F		1,927	D	$11.03	38,017	D
Common								38,017	D
Common								1,191	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:

	William C. Tsonos, by Marissa S. Martin, POA	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 transactions did William C. Tsonos report on Form 4 for BRKL?

He reported multiple dispositions of common shares resulting from vested performance-based restricted stock, executed at $11.03 per share on 08/25/2025.

Why were the shares disposed according to the Form 4?

The Form 4 explains the shares were performance-based restricted stock that vested pursuant to a merger agreement among Berkshire Hills Bancorp, Commerce Acquisition Sub, and Brookline Bancorp.

How many BRKL shares does Mr. Tsonos own after the reported transactions?

The filing shows 38,017 shares owned directly and 1,191 shares owned indirectly through an ESOP.

What does transaction code 'F' indicate on this Form 4?

In this filing the transactions are labeled with code F, and the explanation ties them to the vesting of performance-based restricted stock under the merger agreement.

Was the Form 4 signed directly by Mr. Tsonos?

The signature block shows the Form 4 was executed by a power of attorney on behalf of William C. Tsonos.