UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 12, 2025

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(Exact name of registrant as specified in its charter)

Delaware	001-13695	16-1213679
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

5790 Widewaters Parkway, DeWitt, New York	13214
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (315) 445-2282

Not applicable.

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, $1.00 par value per share	CBU	New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

Item 7.01

Regulation FD Disclosure.

On November 12, 2025, Community Financial System, Inc. (NYSE: CBU) (the “Company”) posted an investor presentation to its website intended for use in upcoming meetings with investors and analysts. The presentation can be accessed on the Events & Presentations page of the Company’s investor relations website at www.communityfinancialsystem.com.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	Community Financial System, Inc.


	By:	/s/ Marya Burgio Wlos
	Name: Marya Burgio Wlos
	Title: Executive Vice President and Chief Financial Officer

Dated: November 12, 2025

COMMUNITY FINANCIAL SYSTEM, INC. 8-K