Deresa Fischer Durkee - 02 Mar 2026 Form 4 Insider Report for COMMUNITY FINANCIAL SYSTEM, INC. (CBU)

Role: SVP, Chief Accounting Officer
Signature: /s/ Danielle M. Cima, pursuant to a Confirming Statement executed by Deresa F. Durkee
Issuer symbol: CBU
Transactions as of: 02 Mar 2026
Net transactions value: $0
Form type: 4
Filing time: 04 Mar 2026, 11:59:51 UTC
Previous filing: 19 Mar 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Durkee Deresa Fischer	SVP, Chief Accounting Officer	C/O COMMUNITY FINANCIAL SYSTEM, INC., 333 BUTTERNUT DRIVE, SYRACUSE	/s/ Danielle M. Cima, pursuant to a Confirming Statement executed by Deresa F. Durkee	04 Mar 2026	0001608689

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	CBU	Common Stock	Tax liability		-357	-6.4%	$60.55^*	5,181	02 Mar 2026	Direct	F1
holding	CBU	Common Stock						646	02 Mar 2026	By 401(k)	F2
holding	CBU	Common Stock						218	02 Mar 2026	By spouse

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Payment of tax liability associated with vesting of restricted stock award.
F2	The number of shares reported herein acquired pursuant to Community Financial System, Inc.'s 401(k) Plan and are based on a current plan statement.