NB Bancorp (NBBK) director discloses new restricted stock award and holdings

Rhea-AI Filing Summary

NB Bancorp, Inc. director reported an equity grant under the company’s stock program. On 01/02/2026, the director acquired 7,685 shares of common stock as restricted stock at a stated price of $0, reflecting an award rather than an open‑market purchase.

After this transaction, the director beneficially owns 96,922 shares of common stock directly and an additional 60,000 shares indirectly through an IRA. The 7,685 restricted shares vest 100% on January 2, 2027, and the direct holdings also include restricted shares that vest at a rate of 20% per year starting on April 24, 2026. This filing shows ongoing equity-based alignment between the director and the company.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Lynch Christopher R.

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	7,685	$0.00	--
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 96,922 shares (Direct); Common Stock — 60,000 shares (Indirect, By IRA)

Footnotes (1)

1. Shares of restricted stock vest 100% on January 2, 2027. Includes shares of restricted stock which vest at a rate of 20% per year commencing on April 24, 2026.

Form 4 Insider Transactions: What Each Field Means →

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^*

Lynch Christopher R.

(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		7,685(1)	A	$0	96,922(2)	D
Common Stock								60,000	I	By IRA

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?

A director of NB Bancorp, Inc. reported acquiring 7,685 shares of restricted common stock on 01/02/2026 at a stated price of $0 as an equity award.

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

Following the award, the director beneficially owns 96,922 shares of common stock directly and 60,000 shares indirectly through an IRA.

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

The 7,685 restricted shares vest 100% on January 2, 2027.

Are there other restricted NB Bancorp (NBBK) shares subject to vesting for this director?

Yes. The holdings include restricted stock that vests at a rate of 20% per year beginning on April 24, 2026.

Is this NB Bancorp (NBBK) insider transaction a purchase on the open market?

The transaction is reported as an acquisition of restricted stock at a price of $0, indicating an equity grant rather than an open‑market purchase.