X0306 4 2017-09-18 0000723188 COMMUNITY BANK SYSTEM, INC. CBU 0001202795 MICHAEL R KALLET C/O COMMUNITY BANK SYSTEM, INC. 5790 WIDEWATERS PARKWAY DEWITT NY 13214 1 Common Stock 2017-09-18 4 S 0 5000 52.5453 D 16603 D Common Stock 66802.639 I By Community Bank System, Inc. 401(k) Plan Common Stock 5606 I By Trust under Will Common Stock 8759 I By Wife Common Stock 1988 I By IRA Phantom Stock (Deferred Compensation) Common Stock 1830.8638 1830.8638 D The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $52.5205 to $52.5796, inclusive. The reporting person undertakes to provide Community Bank System, Inc., any security holder of Community Bank System, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. 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. Includes 17.093 units of phantom stock acquired on July 10, 2017 under the Deferred Compensation Plan's dividend reinvestment feature. Danielle M. Cima, pursuant to a Confirming Statement executed by Michael R. Kallet 2017-09-19