X0306 4 2023-03-14 0000723188 COMMUNITY BANK SYSTEM, INC. CBU 0001485738 Fesette Neil E. C/O COMMUNITY BANK SYSTEM, INC. 5790 WIDEWATERS PARKWAY DEWITT NY 13214 1 Common Stock 8757.1719 D Phantom Stock (Deferred Compensation) Common Stock 7071.9751 7071.9751 D Phantom Stock (Deferred Stock Units) 2023-03-14 4 A 0 1154 0 A Common Stock 1154 3941.2306 D Includes 171.365 shares acquired pursuant to the Community Bank System, Inc. Dividend Reinvestment Plan. Each unit of phantom stock is the economic equivalent of one share of Community Bank System, Inc. common stock. The units of phantom stock relating to the Deferred Compensation Plan will be settled in Community Bank System, Inc. common stock at future dates selected by the reporting person. The reporting person has received deferred stock units under the Community Bank System, Inc. 2022 Long-Term Incentive Plan, as amended (the "Plan"). Each phantom stock unit which represents a deferred stock unit is the economic equivalent of one share of Community Bank System, Inc. common stock and will be settled in common stock at a predetermined date. Includes 74.4395 units of phantom stock acquired as dividend equivalents under the Plan. /s/ Danielle M. Cima, pursuant to a Confirming Statement executed by Neil E. Fesette 2023-03-15