Joseph B. Reilly - 15 Nov 2025 Form 3 Insider Report for NB Bancorp, Inc. (NBBK)

Role: Director
Signature: /s/ Kathleen R. Henry, by Power of Attorney
Issuer symbol: NBBK
Transactions as of: 15 Nov 2025
Transactions value $: $0
Form type: 3
Filing time: 25 Nov 2025, 12:00:32 UTC
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Reilly Joseph B	Director	1063 GREAT PLAIN AVE, NEEDHAM	/s/ Kathleen R. Henry, by Power of Attorney	25 Nov 2025	0001749520

Transactions Table

Type	Sym	Class	Shares After	Date	Ownership	Footnotes
holding	NBBK	Common Stock	12K	15 Nov 2025	Direct	F1
holding	NBBK	Common Stock	36.5K	15 Nov 2025	By Revocable Trust	F2
holding	NBBK	Common Stock	2.4K	15 Nov 2025	By ESOP

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Pursuant to the terms of the Agreement and Plan of Merger, dated June 5, 2025, among NB Bancorp, Inc. ("Needham"), Needham Bank, 1828 MS, Inc., Provident Bancorp, Inc., ("Provident") and BankProv (the "Merger Agreement"), upon the merger of Provident into Needham, effective November 15, 2025 (the "Merger"), each share of Provident common stock was converted into the right to receive, at the election of the holder, either (i) $13.00 in cash or (ii) 0.691 shares of Needham common stock (the "Exchange Ratio"), subject to certain proration and allocation provisions contained in the Merger Agreement.
F2	Pursuant to the terms of the Merger Agreement, each share of Provident common stock was converted into the right to receive, at the election of the holder, (i) $13.00 in cash, or (ii) the Exchange Ratio, subject to certain proration and allocation provisions contained in the Merger Agreement.

Content

Pursuant to the terms of the Agreement and Plan of Merger, dated June 5, 2025, among NB Bancorp, Inc. ("Needham"), Needham Bank, 1828 MS, Inc., Provident Bancorp, Inc., ("Provident") and BankProv (the "Merger Agreement"), upon the merger of Provident into Needham, effective November 15, 2025 (the "Merger"), each share of Provident common stock was converted into the right to receive, at the election of the holder, either (i) $13.00 in cash or (ii) 0.691 shares of Needham common stock (the "Exchange Ratio"), subject to certain proration and allocation provisions contained in the Merger Agreement.

Pursuant to the terms of the Merger Agreement, each share of Provident common stock was converted into the right to receive, at the election of the holder, (i) $13.00 in cash, or (ii) the Exchange Ratio, subject to certain proration and allocation provisions contained in the Merger Agreement.