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): ~~January~~February 2711, 2026

(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 25.02 ~~Results~~Departure of ~~Operations~~Directors ~~and~~or ~~Financial~~Certain ~~Condition~~Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

(d)           On February ~~January 27~~11, 2026, Community Financial System, Inc.’s ~~announced~~(the ~~its~~“Company”) ~~results~~Board of ~~operations~~Directors ~~for~~ (the ~~fourth~~“Board”) ~~quarter~~elected Brenda ~~and~~M. ~~fiscal~~Hall ~~year~~as ~~ended~~a ~~December 31~~new independent director, ~~2025~~effective as of March 1, 2026. ~~The~~Ms. ~~public~~Hall ~~announcement~~is ~~was~~the ~~made~~former byExecutive ~~means~~Vice President and Chief Operating Officer of aStandard ~~news~~Lines ~~release~~(“COO”) at Selective Insurance Group, ~~the~~Inc. ~~text~~(“Selective”), ofwhere ~~which~~she isbuilt a ~~furnished~~distinguished as24-year ~~Exhibit~~career 99marked by progressive advancement and increasing leadership responsibilities.1.

~~The~~During ~~information~~her intenure ~~this~~at ~~Form 8-K~~Selective, ~~including~~Ms. ~~Exhibit~~Hall ~~99.1~~most ~~attached~~recently ~~hereto,~~served isas ~~being~~Chief Operating ~~furnished~~Officer ~~under~~from ~~Item~~October ~~2.02~~2019 ~~and~~until ~~shall~~her ~~not~~retirement bein ~~deemed~~January to2026. ~~be “filed”~~In ~~for~~this ~~purposes~~role, ofshe ~~Section~~oversaw 18the ofcompany’s largest business segment, leading the ~~Securities~~development ~~Exchange~~and ~~Act~~execution of ~~1934~~growth strategies, asexpansion ~~amended~~into ~~(the~~new ~~“Exchange~~geographic ~~Act”)~~markets, orenhancement of data-driven ~~incorporated~~operations, byand ~~reference~~integration inof ~~any~~predictive ~~filing~~modeling ~~under~~into ~~the~~underwriting ~~Securities~~processes. ~~Act~~Prior ofto ~~1933,~~her role as ~~amended~~COO, orMs. ~~the~~Hall ~~Exchange~~held ~~Act~~several senior leadership positions at Selective, ~~except~~including asSenior ~~shall~~Vice bePresident, ~~expressly set~~Chief ~~forth~~Strategic byOperations ~~specific~~Officer, ~~reference~~and inSenior ~~such~~Vice ~~filing~~President, Director of Field Underwriting.

~~Item~~The 9Board has determined that Ms.01 ~~Financial~~Hall ~~Statements~~qualifies as an independent director under New York Stock Exchange and ~~Exhibits~~Board standards. With her appointment, the Board now consists of 14 directors, 13 of whom are independent. Ms. Hall has also joined the Board of Directors of Community Bank, N.A., the Company’s banking subsidiary, and will serve on the Risk Committee of the Company and the Bank.

There are no arrangements or understandings with any person regarding Ms. Hall’s selection as director. Ms. Hall has no related party transactions with the Company requiring disclosure under Item 404(da) ~~Exhibits~~ of Regulation S-K. She will receive compensation consistent with other non-employee directors, as described in the Company’s Proxy Statement on Schedule 14A.

~~The~~A ~~following~~copy ~~exhibit~~of isthe ~~being~~press ~~furnished~~release ~~pursuant~~announcing toMs. ~~Item~~Hall’s appointment 2is attached hereto as Exhibit 99.021 ~~above~~and is incorporated by reference into this Current Report on Form 8-K.

99Item 9.101 ~~Press Release, dated January 27, 2026, issued by Community~~ Financial ~~System,~~Statements ~~Inc.~~and Exhibits

~~104 Cover Page Interactive Data File~~ (~~embedded in the cover page formatted in Inline XBRL~~d)  Exhibits

~~SIGNATURES~~99.1 Press Release, dated February 11, 2026, issued by Community Financial System, Inc.

~~Pursuant~~104 toCover ~~the~~Page ~~requirements~~Interactive ofData ~~the~~File ~~Securities~~(embedded ~~Exchange~~in ~~Act of 1934,~~ the ~~registrant~~cover ~~has~~page ~~duly~~formatted ~~caused~~in ~~this~~Inline ~~report to be signed on its behalf by the undersigned hereunto duly authorized.~~XBRL)

~~Community Financial System, Inc. By: /s/ Marya Burgio Wlos Name: Marya Burgio Wlos Title: Executive Vice President and Chief Financial Officer~~SIGNATURES

~~Dated:~~Pursuant ~~January~~to 27the requirements of the Securities Exchange Act of 1934, ~~2026~~the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

~~Exhibit Index~~Community Financial System, Inc. By: /s/ Michael N. Abdo Name: Michael N. Abdo Title: Executive Vice President and General Counsel

Exhibit Number	Description
99.1	Press Release, dated January 27, 2026, issued by Community Financial System, Inc.
104	Cover Page Interactive Data File (embedded in the cover page formatted in Inline XBRL)

Dated: February 11, 2026

Exhibit Index

Exhibit Number	Description

99.1	Press Release, dated February 11, 2026, issued by Community Financial System, Inc.

104	Cover Page Interactive Data File (embedded in the cover page formatted in Inline XBRL)

Filing Compare · COMMUNITY FINANCIAL SYSTEM, INC.