# EDGAR Filing Document

**Accession Number:** 0000790359
**File Stem:** 0001140361-26-013240
**Filing Date:** 2026-4
**Character Count:** 1902
**Document Hash:** 946b7fc8e77ab0e4d3cd39963ef1d23a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001140361-26-013240.hdr.sgml**: 20260406

**ACCESSION NUMBER**: 0001140361-26-013240

**CONFORMED SUBMISSION TYPE**: DEFA14A

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20260406

**DATE AS OF CHANGE**: 20260406

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** NBT BANCORP INC
- **CENTRAL INDEX KEY:** 0000790359
- **STANDARD INDUSTRIAL CLASSIFICATION:** NATIONAL COMMERCIAL BANKS [6021]
- **ORGANIZATION NAME:** 02 Finance
- **EIN:** 161268674
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** DEFA14A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 000-14703
- **FILM NUMBER:** 26839632

**BUSINESS ADDRESS:**
- **STREET 1:** 52 S BROAD ST
- **CITY:** NORWICH
- **STATE:** NY
- **ZIP:** 13815
- **BUSINESS PHONE:** 6073372265

**MAIL ADDRESS:**
- **STREET 1:** 52 S. BROAD STREET
- **CITY:** NORWICH
- **STATE:** NY
- **ZIP:** 13815

### UNITED STATES <br>

### SECURITIES AND EXCHANGE COMMISSION <br>

### Washington, D.C. 20549

### SCHEDULE 14A

#### Proxy Statement Pursuant to Section 14(a) of the <br>

#### Securities Exchange Act of 1934 (Amendment No.)

#### Filed by Registrant ☑

#### Filed by Party other than the Registrant ☐

#### Check the appropriate box:
☐<br> Preliminary Proxy Statement

☐<br> Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☐ Definitive Proxy Statement

☑ Definitive Additional Materials

☐<br> Soliciting Material Pursuant to §240.14a-12

## NBT Bancorp Inc. <br>

## (Name of Registrant as Specified in Its Charter)

#### Payment of Filing Fee (Check the appropriate box):
☑<br> No fee required.

☐<br> Fee paid previously with preliminary materials.

☐<br> Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rule 14a-6(i)(1) and 0-11.

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