8-K Filing: Director Changes and Board Reclassification

This filing reports significant changes within Financial Institutions, Inc. (the "Company"). Bruce W. Harting has retired from the Board of Directors and the Board of Directors of its subsidiary, Five Star Bank, effective immediately, due to pursuing outside interests. This retirement reduced the Board size from thirteen to twelve members. To maintain balanced class sizes as per the Company's bylaws, Susan R. Holliday, Chair of the Board, resigned from her position in the 2029 class and was immediately reappointed to the 2028 class. This reclassification ensures each of the three Board classes has four members and is considered an uninterrupted continuation of her service. Ms. Holliday retains her role as Chair, with no changes to her committee assignments or compensation. These changes were effective September 1, 2026, and September 3, 2026, respectively.