Annual Statement of Changes in Beneficial Ownership (Form 5)

FORM 5 Check this box if no longer subject to Section 16, Form 4 or Form 5 obligations may continue. See Instruction 1(b). Form 3 Holdings Reported Form 4 Transactions Reported

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ANNUAL STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * Mahoney Ruth H 2. Issuer Name and Ticker or Trading Symbol NBT BANCORP INC [NBTB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) EVP/President of Wealth Mgmt / (Last) (First) (Middle) 52 SOUTH BROAD STREET 3. Statement for Issuer's Fiscal Year Ended (Month/Day/Year) 2025-12-31 (Street) NORWICH NY 13815 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Join/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code 4. Securities Acquired (A) or Disposed of (D) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) 6. Ownership Form: Direct (D) or Indirect (I) 7. Nature of Indirect Beneficial Ownership Amount (A) or (D) Price

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivate Security

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

5. Number of Derivative Securities Acquired (A) or Disposed of (D)

6. Date Exercisable and Expiration Date

7. Title and Amount of Securities Underlying Derivative Security

8. Price of Derivative Security

9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)

11. Nature of Indirect Beneficial Ownership

(A)

(D)

Date Exercisable

Expriation Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Mahoney Ruth H 52 SOUTH BROAD STREET NORWICH, NY13815			EVP/President of Wealth Mgmt

Signatures

By: Annette L. Burns, Power of Attorney For: Ruth H. Mahoney		2026-02-13
**Signature of Reporting Person		Date

Explanation of Responses:

(*)	If the form is filed by more than one reporting person, see Instruction 5(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).
(1)	Shares were purchased through a Dividend Reinvestment Plan from 1/1/2025 to 12/31/2025.
(2)	Shares were purchased through payroll deferral and/or dividend reinvestment from 1/1/2025 to 12/31/2025 through NBT Bancorp Inc. 401k Plan.
(3)	Each share of phantom stock is deemed invested in one share of NBT Bancorp Inc. common stock pursuant to the terms of the Deferred Compensation Plan.
(4)	Shares were purchased through payroll deferral and/or dividend reinvestment from 1/1/2025 to 12/31/2025 through a NBT Bancorp Inc. deferred compensation plan.

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