Community Bank System, Inc. Announces Senior Management Changes

Syracuse, NY August 25, 2022 — Community Bank System, Inc. (NYSE: CBU) (the “Company”) announced two senior management changes. Joseph F. Serbun, President, Retail Banking, of the Company and its wholly owned subsidiary, Community Bank, N.A. (the “Bank”), has decided to retire after more than 14 years of service. Mr. Serbun joined the Bank in January 2008 and has served in important senior management roles including Chief Credit Officer, Chief Banking Officer, and President, Retail Banking, playing an instrumental role in the Bank’s growth and success. Mr. Serbun will retire from his position effective as of September 30, 2022.

Mark E. Tryniski, the President and Chief Executive Officer (“CEO”) of the Company and the Bank commented, “Joe has served as an important leader of the Bank and the Company and has been responsible for shaping our culture and growth for the past 14 years. We will miss Joe and wish him the best in his retirement.”

In addition, the Company announced that it has promoted Dimitar Karaivanov to Executive Vice President and Chief Operating Officer of the Company and the Bank effective October 1, 2022. Mr. Karaivanov has served as Executive Vice President of Financial Services and Corporate Development since joining the Company in June 2021. In his role as Chief Operating Officer, Mr. Karaivanov will have oversight responsibilities for all banking, wealth management, employee benefit services, and insurance operations and related business activities.

Mr. Tryniski commented, “I am excited to announce the appointment of Dimitar Karaivanov as the Company’s Chief Operating Officer. Since joining the Company, Dimitar has brought fresh ideas and innovative thinking to his role as the Executive Vice President of Financial Services and Corporate Development. Dimitar has effectively led the Company’s mergers and acquisition strategy and reshaped the Company’s wealth management, employee benefit services, and insurance business units. Through this appointment, he will begin to focus his attention on our banking operations in order to optimize our core business with a focus on increased revenue growth.”

Community Bank System, Inc. operates over 220 customer facilities across Upstate New York, Northeastern Pennsylvania, Vermont, and Western Massachusetts through its banking subsidiary, Community Bank, N.A. With assets of over $15.4 billion, the DeWitt, N.Y. headquartered company is among the country’s 125 largest banking institutions. In addition to a full range of retail, business, and municipal banking services, the Company offers comprehensive financial planning, insurance, and wealth management services through its Community Bank Wealth Management Group and OneGroup NY, Inc. operating units. The Company’s Benefit Plans Administrative Services, Inc. subsidiary is a leading provider of employee benefits administration, trust services, collective investment fund administration and actuarial consulting services to customers on a national scale. Community Bank System, Inc. is listed on the New York Stock Exchange and the Company’s stock trades under the symbol CBU. For more information about Community Bank visit www.cbna.com or http://ir.communitybanksystem.com.