Regulation FD Disclosure. Financial Institutions, Inc. (the “Company”) issued a press release announcing that on August 26, 2026, its Board of Directors declared a cash dividend of $0.32 per common share. The Company also announced dividends of $0.75 per share on Series A 3% Preferred Stock and $2.12 per share on Series B-1 8.48% Preferred Stock. All dividends are payable October 2, 2026 to shareholders of record as of September 15, 2026. The press release issued by the Company is furnished a…

Results of Operations and Financial Condition. On July 23, 2026, Financial Institutions, Inc. (the “Company”) issued a press release to report financial results for the second quarter ended June 30, 2026. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Regulation FD Disclosure. Financial Institutions, Inc. (the “Company”) issued a press release announcing that on February 12, 2026, its Board of Directors declared a cash dividend of $0.32 per common share. The Company also announced dividends of $0.75 per share on Series A 3% Preferred Stock and $2.12 per share on Series B-1 8.48% Preferred Stock. All dividends are payable July 2, 2026 to shareholders of record as of June 12, 2026. The press release issued by the Company is furnished as Exhi…

Results of Operations and Financial Condition. On April 23, 2026, Financial Institutions, Inc. (the “Company”) issued a press release to report financial results for the first quarter ended March 31, 2026. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Director — Donald K. Boswell: Mr. Boswell decided not to stand for re-election due to his intent to pursue outside interests.

Regulation FD Disclosure. Financial Institutions, Inc. (the “Company”) issued a press release announcing that on February 12, 2026, its Board of Directors declared a cash dividend of $0.32 per common share. The Company also announced dividends of $0.75 per share on Series A 3% Preferred Stock and $2.12 per share on Series B-1 8.48% Preferred Stock. All dividends are payable April 2, 2026 to shareholders of record as of March 13, 2026. The press release issued by the Company is furnished as Ex…

Results of Operations and Financial Condition. On January 29, 2026, Financial Institutions, Inc. (the “Company”) issued a press release to report financial results for the fourth quarter ended December 31, 2025. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant The information set forth and incorporated by reference in

Entry into a Material Definitive Agreement On December 11, 2025, Financial Institutions, Inc. (the “Company”) entered into Subordinated Note Purchase Agreements (collectively, the “Subordinated Note Purchase Agreements”) with certain qualified institutional buyers and institutional accredited investors (collectively, the “Subordinated Note Purchasers”) pursuant to which the Company issued $80.0 million in aggregate principal amount of its 6.50% Fixed-to-Floating Rate Subordinated Notes due 20…

Regulation FD Disclosure. Financial Institutions, Inc. (the “Company”) issued a press release announcing that on November 14, 2025, its Board of Directors declared a cash dividend of $0.31 per common share. The Company also announced dividends of $0.75 per share on Series A 3% Preferred Stock and $2.12 per share on Series B-1 8.48% Preferred Stock. All dividends are payable January 2, 2026 to shareholders of record as of December 15, 2025. The press release issued by the Company is furnished…

Results of Operations and Financial Condition. On October 23, 2025, Financial Institutions, Inc. (the “Company”) issued a press release to report financial results for the third quarter ended September 30, 2025. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Regulation FD Disclosure. On September 22, 2025, Financial Institutions, Inc. (the “Company”) issued a press release announcing that its Board of Directors (“Board”) has approved a new share repurchase program for up to 1,006,379 shares of its common stock, or approximately 5% of the Company’s current outstanding common shares. Effective September 18, 2025, the new share repurchase program replaces and terminates the prior share repurchase program authorized by the Board in June 2022. The new…

Regulation FD Disclosure. Financial Institutions, Inc. (the “Company”) issued a press release announcing the declaration of a cash dividend of $0.31 per common share on August 25, 2025. The Company also announced dividends of $0.75 per share on Series A 3% Preferred Stock and $2.12 per share on Series B-1 8.48% Preferred Stock. All dividends are payable October 2, 2025 to shareholders of record as of September 15, 2025. The press release issued by the Company is furnished as Exhibit 99.1 to t…

Results of Operations and Financial Condition. On July 24, 2025, Financial Institutions, Inc. (the “Company”) issued a press release to report financial results for the second quarter ended June 30, 2025. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

The filing describes a shareholder approval of amendments to the long-term incentive plan, which is not directly related to management changes.

Regulation FD Disclosure. Financial Institutions, Inc. (the “Company”) issued a press release announcing the declaration of a cash dividend of $0.31 per common share on May 28, 2025. The Company also announced dividends of $0.75 per share on Series A 3% Preferred Stock and $2.12 per share on Series B-1 8.48% Preferred Stock. All dividends are payable July 2, 2025 to shareholders of record as of June 13, 2025. The press release issued by the Company is furnished as Exhibit 99.1 to this Form 8-…

Results of Operations and Financial Condition. On April 28, 2025, Financial Institutions, Inc. (the “Company”) issued a press release to report financial results for the first quarter ended March 31, 2025. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Entry into a Material Definitive Agreement. On March 7, 2025, Financial Institutions, Inc. (the “Company”), parent company of Five Star Bank (the “Bank”), entered into a Settlement Agreement (the “Settlement Agreement”) with plaintiffs in the previously disclosed class action lawsuit to which the Company and the Bank are parties, brought by borrowers in New York and Pennsylvania in Pennsylvania state court regarding notices the Bank sent to defaulting borrowers after their vehicles were repos…

Results of Operations and Financial Condition. On January 30, 2025, the Company announced financial results for the fiscal year and fourth quarter ended December 31, 2024. Subsequent to issuing the Original Earnings Release and based on new information, the Company recorded a loss contingency related to the previously disclosed class action lawsuit to which the Company and the Bank are parties, brought by borrowers in New York and Pennsylvania regarding notices the Bank sent to defaulting bor…

Director — Samuel M. Gullo: Samuel M. Gullo is retiring from the Board of Directors after 25 years of service.

Regulation FD Disclosure. Financial Institutions, Inc. (the “Company”) issued a press release announcing the declaration of a cash dividend of $0.31 per common share on February 12, 2025. The Company also announced dividends of $0.75 per share on Series A 3% Preferred Stock and $2.12 per share on Series B-1 8.48% Preferred Stock. All dividends are payable April 2, 2025 to shareholders of record as of March 14, 2025. The press release issued by the Company is furnished as Exhibit 99.1 to this…

Results of Operations and Financial Condition. On January 30, 2025, Financial Institutions, Inc. (the “Company”) issued a press release to report financial results for the fourth quarter ended December 31, 2024. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Director — Angela J. Panzarella: The company appointed a new independent director to its board.

Entry into a Material Definitive Agreement. On December 11, 2024, Financial Institutions, Inc. (the “Company”), a financial holding company organized under the laws of New York State that operates through its wholly owned banking subsidiary, Five Star Bank (the “Bank”), entered into an underwriting agreement (the “Underwriting Agreement”) with Keefe, Bruyette & Woods, Inc., as representative of the several underwriters named in Schedule I thereto (collectively, the “Underwriters”), to issue a…

Other Events. On December 11, 2024, the Company issued a press release announcing the launch of the Offering, which is attached as Exhibit 99.1 hereto and is incorporated herein by reference. On December 11, 2024, the Company issued a press release announcing the pricing of the Offering, which is attached as Exhibit 99.2 hereto and is incorporated herein by reference. Special Note Concerning Forward-Looking Statements This Current Report on Form 8-K contains forward-looking statements within…