STOCK TITAN

NB Bancorp (NBBK) director reports tax-withholding share disposition and holdings

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

NB Bancorp, Inc. director Christopher R. Lynch reported routine share updates, including a tax-related share disposition. On April 24, 2026, 4,150 shares of common stock were disposed of at $19.82 per share to cover tax obligations, a non-market “F” code transaction. After this, he held 92,772 common shares directly and 60,000 shares indirectly through an IRA. Footnotes note that his holdings include restricted stock that vests 20% per year starting April 24, 2026 and additional restricted stock vesting 100% on January 2, 2027.

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Insider Lynch Christopher R.
Role null
Type Security Shares Price Value
Tax Withholding Common Stock 4,150 $19.82 $82K
holding Common Stock -- -- --
Holdings After Transaction: Common Stock — 92,772 shares (Direct, null); Common Stock — 60,000 shares (Indirect, By IRA)
Footnotes (1)
  1. Includes shares of restricted stock which vest at a rate of 20% per year commencing on April 24, 2026. Includes shares of restricted stock which vest 100% on January 2, 2027.
Tax-withholding shares 4,150 shares Common Stock, code F disposition on April 24, 2026
Tax-withholding price $19.82 per share Value applied to 4,150-share tax-withholding disposition
Direct holdings after transaction 92,772 shares Common Stock directly owned following April 24, 2026 event
Indirect holdings via IRA 60,000 shares Common Stock held indirectly by IRA as of April 24, 2026
Restricted stock vesting start April 24, 2026 Restricted stock vests 20% per year commencing on this date
Single-date vesting January 2, 2027 Restricted stock tranche vests 100% on this date
tax-withholding disposition financial
"transaction_action: "tax-withholding disposition" for the F-code entry"
A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.
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.
Common Stock financial
"security_title: "Common Stock" for both reported entries"
Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.
IRA financial
"nature_of_ownership: "By IRA" for the indirect holdings entry"
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.
SEC Form 4
FORM 4UNITED 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 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)
XDirector10% Owner
Officer (give title below)Other (specify below)
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
04/24/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock04/24/2026F4,150D$19.8292,772(1)(2)D
Common Stock60,000IBy 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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount 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. Includes shares of restricted stock which vest 100% on January 2, 2027.
/s/ Steven Lanter, pursuant to power of attorney04/27/2026
** Signature of Reporting PersonDate
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)

FAQ

What insider transaction did NB Bancorp (NBBK) report for Christopher R. Lynch?

NB Bancorp director Christopher R. Lynch reported a Form 4 transaction where 4,150 common shares were disposed of on April 24, 2026 as a tax-withholding event at $19.82 per share, rather than an open-market sale, reflecting routine tax settlement.

How many NB Bancorp (NBBK) shares does Christopher R. Lynch hold after this Form 4?

After the reported activity, Christopher R. Lynch holds 92,772 NB Bancorp common shares directly and 60,000 shares indirectly through an IRA. These totals include restricted stock awards that are scheduled to vest on future dates as disclosed in the footnotes.

Was the NB Bancorp (NBBK) Form 4 transaction an open-market sale?

No, the Form 4 shows a code “F” transaction, which is a tax-withholding disposition. Shares were delivered at $19.82 per share to satisfy tax obligations, not sold in the open market, making this a routine administrative event rather than a discretionary sale.

What price per share applied to the NB Bancorp (NBBK) tax-withholding shares?

The 4,150 NB Bancorp common shares involved in the tax-withholding disposition were valued at $19.82 per share. This price is used to calculate the value of shares delivered to cover tax liabilities associated with equity awards for the reporting person.

What restricted stock vesting schedule is disclosed for NB Bancorp (NBBK) director Lynch?

The filing notes that some of Christopher R. Lynch’s holdings are restricted stock that vest 20% per year beginning April 24, 2026. Additional restricted stock is scheduled to vest 100% on January 2, 2027, affecting when he fully gains access to those shares.

How are indirect NB Bancorp (NBBK) holdings reported for Christopher R. Lynch?

The Form 4 reports 60,000 NB Bancorp common shares held indirectly by Christopher R. Lynch through an IRA. This indirect ownership is indicated with an “I” code and the nature-of-ownership description “By IRA,” distinguishing it from his directly held shares.