COMMUNITY FINANCIAL SYSTEM, INC. — Director's Dealing 2018

May 31, 2018

SEC Form 3/A — Form 3/A

Issuer: COMMUNITY BANK SYSTEM, INC. (CBU)
CIK: 0000723188
Period of Report: 2018-05-21

Reporting Person: Serbun Joseph F (EVP, Chief Credit Officer)

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	546.7621	Indirect
Common Stock	8226.7224	Direct

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Stock Option	$19.48	2020-01-20	Common Stock (82)		Direct
Stock Option	$27.36	2021-01-19	Common Stock (2599)		Direct
Stock Option	$28.78	2022-03-21	Common Stock (3484)		Direct
Stock Option	$29.79	2023-03-19	Common Stock (3858)		Direct
Stock Option	$35.36	2025-03-18	Common Stock (3053)		Direct
Stock Option	$37.77	2024-03-19	Common Stock (2935)		Direct
Stock Option	$38.02	2026-03-16	Common Stock (4029)		Direct
Stock Option	$55.92	2028-03-20	Common Stock (2779)		Direct
Stock Option	$57.12	2027-03-15	Common Stock (2357)		Direct

Footnotes

F1: This Amendment is filed to include the reporting person's Confirming Statement.

F2: The number of shares reported herein acquired pursuant to Community Bank System, Inc.'s 401(k) Plan and are based on a current plan statement.

F3: The option vested ratably on January 20, 2011, 2012, 2013, 2014 and 2015.

F4: The option vested ratably on January 19, 2012, 2013, 2014, 2015 and 2016.

F5: The option vested ratably on March 21, 2013, 2014, 2015, 2016 and 2017.

F6: The option vested ratably on March 19, 2014, 2015, 2016, 2017 and 2018.

F7: The option vests ratably on March 18, 2016, 2017, 2018, 2019 and 2020.

F8: The option vests ratably on March 19, 2015, 2016, 2017, 2018 and 2019.

F9: The option vests ratably on March 16, 2017, 2018, 2019, 2020 and 2021.

F10: The option vests ratably on March 20, 2019, 2020, 2021, 2022 and 2023.

F11: The option vests ratably on March 15, 2018, 2019, 2020, 2021 and 2022.