Results of Operations and Financial Condition On July 27, 2026, NBT Bancorp Inc. (the “Company”) issued a press release describing its results of operations for the quarter ended June 30, 2026. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Tuesday, July 28, 2026, to review the second quarter 2026 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the Event Cale…

Regulation FD Disclosure. On May 19, 2026, the Company approved a second-quarter 2026 cash dividend of $0.37 per share. The dividend will be paid on June 15, 2026 to shareholders of record on June 1, 2026. That press release is furnished as Exhibit 99.1 hereto.

Results of Operations and Financial Condition On April 23, 2026, NBT Bancorp Inc. (the “Company”) issued a press release describing its results of operations for the quarter ended March 31, 2026. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Friday, April 24, 2026, to review the first quarter 2026 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the Event Cal…

Chief Credit Officer — Amy C. Wiles: The executive is transitioning to a non-executive advisory role and retiring in 2027, representing an orderly succession rather than a sudden loss of leadership.

Results of Operations and Financial Condition On January 26, 2026, NBT Bancorp Inc. (the “Company”) issued a press release describing its results of operations for the quarter ended December 31, 2025. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Tuesday, January 27, 2026, to review the fourth quarter 2025 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the…

Results of Operations and Financial Condition On October 27, 2025, NBT Bancorp Inc. issued a press release describing its results of operations for the quarter ended September 30, 2025. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Tuesday, October 28, 2025, to review the third quarter 2025 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the Event Calendar p…

Results of Operations and Financial Condition On July 28, 2025, NBT Bancorp Inc. issued a press release describing its results of operations for the quarter ended June 30, 2025. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Tuesday, July 29, 2025, to review the second quarter 2025 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the Event Calendar page of the…

Director — David J. Nasca: The filing discloses the appointment of a new director to the board following an annual meeting, which is a routine governance event rather than an executive departure.

Regulation FD Disclosure. On May 20, 2025, NBT approved a second-quarter 2025 cash dividend of $0.34 per share. The dividend will be paid on June 16, 2025 to shareholders of record on June 2, 2025. That press release is furnished as Exhibit 99.1 hereto.

Completion of Acquisition or Disposition of Assets. As previously disclosed, on September 9, 2024, NBT Bancorp Inc. (the “Company” or “NBT”) and NBT Bank, National Association, the Company’s subsidiary bank (“NBT Bank”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Evans Bancorp, Inc. (“Evans”) and Evans Bank, National Association, Evans’s subsidiary bank (“Evans Bank”). On May 2, 2025, NBT completed its a cquisition of Evans pursuant to the Merger Agreement thro…

Results of Operations and Financial Condition On April 24, 2025, NBT Bancorp Inc. issued a press release describing its results of operations for the quarter ended March 31, 2025. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Friday, April 25, 2025, to review the first quarter 2025 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the Event Calendar page of th…

Scott A. Kingsley: The filing discloses an amendment to a supplemental retirement plan (compensatory arrangement) rather than a change in officer or director status.

Results of Operations and Financial Condition On January 27, 2025, NBT Bancorp Inc. issued a press release describing its results of operations for the quarter ended December 31, 2024. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Tuesday, January 28, 2025, to review the fourth quarter 2024 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the Event Calendar p…

Other Events On December 20, 2024, NBT Bancorp Inc. (“NBT”) and Evans Bancorp, Inc. (“Evans”) issued a press release announcing that they had received the requisite regulatory approvals and waivers from the Office of the Comptroller of the Currency and the Federal Reserve Bank of New York necessary for NBT to complete its acquisition of Evans and Evans Bank and that the shareholders of Evans voted to approve the merger. NBT and Evans anticipate closing the transaction in the second quarter of…

Other Events As previously disclosed, on September 9, 2024, Evans Bancorp, Inc. (“Evans”) and its wholly-owned subsidiary, Evans Bank, National Association (“Evans Bank”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) with NBT Bancorp Inc. (“NBT”) and NBT Bank, National Association (“NBT Bank”), pursuant to which Evans will merge with and into NBT, with NBT as the surviving entity (the “Merger”). In connection with the proposed Merger, NBT filed with the Securities and…

Results of Operations and Financial Condition On October 28, 2024, NBT Bancorp Inc. issued a press release describing its results of operations for the quarter ended September 30, 2024. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Tuesday, October 29, 2024, to review the third quarter 2024 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the Event Calendar p…

Entry into a Material Definitive Agreement. On September 9, 2024, NBT Bancorp Inc. (the “Company”) and NBT Bank, National Association (“NBT Bank”), the Company’s subsidiary bank, entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Evans Bancorp, Inc. (“Evans”) and Evans Bank, National Association (“Evans Bank”), Evans’s subsidiary bank, and pursuant to which the Company will acquire Evans. Subject to the terms and conditions of the Merger Agreement, which has been appro…

Results of Operations and Financial Condition On July 22, 2024, NBT Bancorp Inc. issued a press release describing its results of operations for the quarter ended June 30, 2024. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Tuesday, July 23, 2024, to review the second quarter 2024 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the Event Calendar page of the…

CEO — Scott A. Kingsley: The filing documents the formalization of Scott A. Kingsley's appointment as President and CEO, which is a succession event rather than a departure.

Regulation FD Disclosure. On May 21, 2024, NBT approved a second-quarter 2024 cash dividend of $0.32 per share. The dividend will be paid on June 17, 2024 to shareholders of record on June 3, 2024. That press release is furnished as Exhibit 99.2 hereto.

The filing discloses the approval of a new equity incentive plan, which is a compensatory arrangement rather than a change in management personnel.

Results of Operations and Financial Condition On April 22, 2024, NBT Bancorp Inc. issued a press release describing its results of operations for the quarter ended March 31, 2024. That press release is furnished as Exhibit 99.1 hereto. A conference call will be held at 10:00 a.m. Eastern Time on Tuesday, April 23, 2024, to review the first quarter 2024 financial results. The audio webcast link, along with the corresponding presentation slides, will be available on the Event Calendar page of t…