NB Bancorp, Inc. (NBBK) director reports 4,803-share restricted stock award

Rhea-AI Filing Summary

NB Bancorp, Inc. reported an insider equity transaction by one of its directors. On January 2, 2026, the director acquired 4,803 shares of NB Bancorp common stock as a grant of restricted stock at a stated price of $0 per share. After this grant, the director beneficially owns a total of 85,140 shares of common stock in direct form.

The filing explains that the 4,803 restricted shares vest 100% on January 2, 2027, and that the total also includes other restricted shares that vest at a rate of 20% per year starting on April 24, 2026. This reflects ongoing equity-based compensation aligning the director’s holdings with the company’s stock over a multi‑year schedule.

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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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^*

Montgomery Kenneth C.

(Last) (First) (Middle)

1063 GREAT PLAIN AVE

(Street)

NEEDHAM MA 02492

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
NB Bancorp, Inc. [ NBBK ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
01/02/2026

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 Stock	01/02/2026		A		4,803(1)	A	$0	85,140(2)	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. Shares of restricted stock vest 100% on January 2, 2027.

2. Includes shares of restricted stock which vest at a rate of 20% per year commencing on April 24, 2026.

	/s/ Steven Lanter, pursuant to power of attorney	01/06/2026
	** 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 insider transaction did NB Bancorp, Inc. (NBBK) report in this Form 4?

NB Bancorp, Inc. reported that a director acquired 4,803 shares of its common stock on January 2, 2026 as a grant of restricted stock at a stated price of $0 per share.

How many NB Bancorp (NBBK) shares does the reporting person own after this transaction?

Following the reported transaction, the director beneficially owns 85,140 shares of NB Bancorp common stock in direct ownership, including restricted shares subject to vesting.

When do the newly granted restricted NB Bancorp (NBBK) shares vest?

The filing states that the 4,803 shares of restricted stock granted on January 2, 2026 will vest 100% on January 2, 2027.

Are there other restricted NB Bancorp (NBBK) shares with a vesting schedule?

Yes. The total holdings include shares of restricted stock that vest at a rate of 20% per year, beginning on April 24, 2026, as disclosed in the explanation of responses.

What is the relationship of the reporting person to NB Bancorp, Inc. (NBBK)?

The reporting person is identified as a director of NB Bancorp, Inc., as indicated in the relationship section of the filing.

Is this NB Bancorp (NBBK) Form 4 filed for an individual or a group?

The document indicates that the Form is filed by one reporting person, not by more than one reporting person.