NB Bancorp CEO buys 2,000 shares at $21.75

NB Bancorp, Inc. (NBBK) reported that President, CEO and Chairman Joseph P. Campanelli purchased 2,000 shares of common stock on August 20, 2026 at $21.75 per share in an open-market or private transaction.

Rhea-AI Filing Summary

NB Bancorp, Inc. (NBBK) reported that President, CEO and Chairman Joseph P. Campanelli purchased 2,000 shares of common stock on August 20, 2026 at $21.75 per share in an open-market or private transaction. Following this buy, his directly held stake rose to 379,790 shares, which includes restricted stock that vests 20% per year beginning April 24, 2026 and other restricted shares vesting 33 1/3% per year beginning February 25, 2027.

Campanelli also reports indirect holdings of 47,000 shares through an IRA, 3,000 shares as trustee for a trust, 51,220 shares via a 401(k), and 3,677 shares through an ESOP.

Insider Trade Summary

Net Buyer: 2,000 shares

Net Buy 5 txns

Insider CAMPANELLI JOSEPH P

Role President & CEO

Bought 2,000 shs ($44K)

Type	Security	Shares	Price	Value
Purchase	Common Stock F1, F2	2,000	$21.75	$44K
holding	Common Stock	--	--	--
holding	Common Stock	--	--	--
holding	Common Stock	--	--	--
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 379,790 shares (Direct); Common Stock — 47,000 shares (Indirect, By IRA); Common Stock — 3,000 shares (Indirect, As trustee for trust); Common Stock — 51,220 shares (Indirect, By 401(k)); Common Stock — 3,677 shares (Indirect, By ESOP)

Footnotes (2)

1. F1. Includes shares of restricted stock which vest at a rate of 20% per year commencing on April 24, 2026.
2. F2. Shares of restricted stock vest at a rate of 33 1/3% per year commencing on February 25, 2027.

Key Figures

Shares purchased: 2,000 shares of Common Stock Purchase price per share: $21.75 per share Direct holdings after transaction: 379,790 shares +5 more

8 metrics

Shares purchased 2,000 shares of Common Stock Purchase on August 20, 2026

Purchase price per share $21.75 per share Open-market or private transaction on August 20, 2026

Direct holdings after transaction 379,790 shares Common Stock directly owned following August 20, 2026 purchase

Indirect holdings via IRA 47,000 shares Common Stock held indirectly by IRA

Indirect holdings via 401(k) 51,220 shares Common Stock held indirectly by 401(k)

Indirect holdings via ESOP 3,677 shares Common Stock held indirectly by ESOP

Restricted stock vesting rate 1 20% per year Restricted stock vesting commencing April 24, 2026

Restricted stock vesting rate 2 33 1/3% per year Restricted stock vesting commencing February 25, 2027

Key Terms

restricted stock, ESOP, IRA, 401(k)

4 terms

restricted stock financial

"Includes shares of restricted stock which vest at a rate of 20% per year"

Shares granted to an individual that carry limits on transfer or sale until certain conditions are met, such as staying with the company for a set time or hitting performance targets. Think of them as a locked gift that gradually opens; for investors they matter because they affect how many shares may enter the market later, signal management incentives and potential dilution, and reveal confidence in future company performance.

ESOP financial

"Indirect ownership nature described as "By ESOP""

An Employee Stock Ownership Plan (ESOP) is a program that gives employees ownership shares in their company, often as part of their benefits package. It acts like a company-sponsored savings plan, allowing workers to have a stake in the company's success, which can boost motivation and loyalty. For investors, ESOPs can influence company decisions and stock value, making them an important aspect of corporate ownership and governance.

IRA financial

"Indirect ownership nature described as "By IRA""

An individual retirement account (IRA) is a savings account designed to help people put aside money for their retirement, often with tax advantages that encourage long-term savings. It matters to investors because it can grow over time, providing financial security later in life, and offers benefits that can reduce current taxes or allow investments to compound more effectively.

401(k) financial

"Indirect ownership nature described as "By 401(k)""

A 401(k) is a type of retirement savings plan offered by employers that allows workers to set aside a portion of their paycheck before taxes are taken out. The money saved in a 401(k) can grow over time through investments, helping individuals build funds for their future retirement. It matters to investors because it provides a tax-advantaged way to save and invest for long-term financial security.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did NB Bancorp (NBBK) disclose for Joseph P. Campanelli?

NB Bancorp disclosed that Joseph P. Campanelli purchased 2,000 shares of common stock on August 20, 2026 at $21.75 per share, increasing his directly held position to 379,790 shares, including restricted stock subject to vesting schedules.

At what price did the NBBK CEO buy shares in this Form 4 filing?

Joseph P. Campanelli bought NB Bancorp common stock at $21.75 per share on August 20, 2026. The transaction was reported with the Form 4 code for a purchase in an open-market or private transaction.

How many NB Bancorp (NBBK) shares does the CEO hold directly after this transaction?

After the reported purchase, Joseph P. Campanelli directly holds 379,790 shares of NB Bancorp common stock. This figure includes shares of restricted stock that vest over time under two separate vesting schedules beginning in 2026 and 2027.

What indirect NB Bancorp (NBBK) holdings does Joseph P. Campanelli report?

Joseph P. Campanelli reports indirect NB Bancorp holdings of 47,000 shares via an IRA, 3,000 shares as trustee for a trust, 51,220 shares through a 401(k), and 3,677 shares through an ESOP, in addition to his direct holdings.

Does this NB Bancorp (NBBK) Form 4 transaction involve a Rule 10b5-1 plan?

The filing indicates the Rule 10b5-1 checkbox is not checked, so the reported purchase of 2,000 shares at $21.75 per share was not affirmed as being made under a Rule 10b5-1 trading plan.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/21/2026 - 04:58 PM Accepted by SEC EDGAR 08/21/2026 - 04:57 PM Learn about SEC filing dates

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^*

CAMPANELLI JOSEPH P

(Last) (First) (Middle)

1063 GREAT PLAIN AVE

(Street)

NEEDHAM MASSACHUSETTS 02492

(City) (State) (Zip)

UNITED STATES

(Country)

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
X	Officer (give title below)	X	Other (specify below)
	President & CEO		Chairman of the Board

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/20/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	08/20/2026		P		2,000	A	$21.75	379,790(1)(2)	D
Common Stock								47,000	I	By IRA
Common Stock								3,000	I	As trustee for trust
Common Stock								51,220	I	By 401(k)
Common Stock								3,677	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. Includes shares of restricted stock which vest at a rate of 20% per year commencing on April 24, 2026.

2. Shares of restricted stock vest at a rate of 33 1/3% per year commencing on February 25, 2027.

Remarks:

Exhibit List: Exhibit 24 - Power of Attorney

	/s/ Kate Henry, by Power of Attorney	08/21/2026
	** 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.
* Form 4: SEC 1474 (03-26)