Transaction Details

Footnotes

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $64.00 to $64.255, inclusive. The reporting person undertakes to provide Community Financial System, Inc., any security holder of Community Financial 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. | The reporting person has received deferred stock units under the Community Financial 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 Financial System, Inc. common stock and will be settled in common stock at a predetermined date. | Includes 9.4706, 10.4729, and 9.6079 units of phantom stock acquired on July 10, 2025, October 10, 2025, and January 12, 2026, respectively, under the Plan's dividend reinvestment feature.