# EDGAR Filing Document

**Accession Number:** 0001749520
**File Stem:** 0001104659-25-115779
**Filing Date:** 2025-11
**Character Count:** 5100
**Document Hash:** 234399280ef98d546ddd7a9a88abac0d
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-115779.hdr.sgml**: 20251125

**ACCESSION NUMBER**: 0001104659-25-115779

**CONFORMED SUBMISSION TYPE**: 3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20251115

**FILED AS OF DATE**: 20251125

**DATE AS OF CHANGE**: 20251125

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Reilly Joseph B
- **CENTRAL INDEX KEY:** 0001749520

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-41899
- **FILM NUMBER:** 251516662

**MAIL ADDRESS:**
- **STREET 1:** 5 MARKET STREET
- **CITY:** AMESBURY
- **STATE:** MA
- **ZIP:** 01913
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** NB Bancorp, Inc.
- **CENTRAL INDEX KEY:** 0001979330
- **STANDARD INDUSTRIAL CLASSIFICATION:** SAVINGS INSTITUTIONS, NOT FEDERALLY CHARTERED [6036]
- **ORGANIZATION NAME:** 02 Finance
- **EIN:** 932560883
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 1063 GREAT PLAIN AVENUE
- **CITY:** NEEDHAM
- **STATE:** MA
- **ZIP:** 02492
- **BUSINESS PHONE:** 781-444-2100

**MAIL ADDRESS:**
- **STREET 1:** 1063 GREAT PLAIN AVENUE
- **CITY:** NEEDHAM
- **STATE:** MA
- **ZIP:** 02492

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 3

### INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Reilly Joseph B<br><sub>(Last) (First) (Middle)</sub><br>1063 GREAT PLAIN AVE<br><sub>(Street)</sub><br>NEEDHAM, MA 02492<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>NB Bancorp, Inc. [ NBBK ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2025-11-15 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director   [ ] 10% Owner<br>[ ] Officer (give title below)   [ ] Other (specify below)<br>_ _ | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities Beneficially Owned

---

|  |  |  |  |
| --- | --- | --- | --- |
| 1. Title of Security | 2. Amount of Securities Beneficially Owned | 3. Ownership Form | 4. Nature of Indirect Beneficial Ownership |
| Common Stock | 12012 | D<sup>(1)</sup> |  |
| Common Stock | 36465 | I<sup>(2)</sup> | By Revocable Trust |
| Common Stock | 2398 | I | By ESOP |

---

## Table II - Derivative Securities Beneficially Owned

---

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 3. Title and Amount of Underlying Securities | 3. Title and Amount of Underlying Securities | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
|  |  |  |  |  |  |  |  |

---

### Footnotes:

(1) 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.

(2) 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.

**Signature:** /s/ Kathleen R. Henry, by Power of Attorney  
**Date:** 2025-11-25

### Remarks:

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.**