X0508 4 2024-03-19 0000723188 COMMUNITY BANK SYSTEM, INC. CBU 0001201821 STICKELS ERIC C/O COMMUNITY BANK SYSTEM, INC. 5790 WIDEWATERS PARKWAY DEWITT NY 13214 1 0 Common Stock 34888 D Common Stock 14507.1013 I By Wife's Community Bank System, Inc. 401(k) Phantom Stock (Deferred Stock Units) 2024-03-19 4 A 0 1395 0 A Common Stock 1395 3262.5819 D The reporting person's directly owned shares have been reduced by 1.9727 shares to adjust for fractional shares that were previously reported as acquired by the reporting person but were paid out in cash. The fractional shares were included in the deferred stock units distributions reported on November 17, 2022, March 16, 2023, November 16, 2023, and March 19, 2024. 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. Danielle M. Cima, pursuant to a Confirming Statement executed by Eric E. Stickels 2024-03-21