Neil E. Fesette - 18 Dec 2025 Form 4 Insider Report for COMMUNITY FINANCIAL SYSTEM, INC. (CBU)

Role: Director
Signature: /s/ Danielle M. Cima, pursuant to a Confirming Statement executed by Neil E. Fesette
Issuer symbol: CBU
Transactions as of: 18 Dec 2025
Net transactions value: +$11,500
Form type: 4
Filing time: 19 Dec 2025, 10:53:38 UTC
Previous filing: 22 Sep 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Fesette Neil E.	Director	C/O COMMUNITY FINANCIAL SYSTEM, INC., 5790 WIDEWATERS PARKWAY, DEWITT	/s/ Danielle M. Cima, pursuant to a Confirming Statement executed by Neil E. Fesette	19 Dec 2025	0001485738

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
holding	CBU	Common Stock						11,202	18 Dec 2025	Direct	F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	CBU	Phantom Stock (Deferred Compensation)	Award	$11,500	+189	+2.5%	$60.69	7,713	18 Dec 2025	Common Stock	189		Direct	F4, F5
holding	CBU	Phantom Stock (Deferred Stock Units)						6,963	18 Dec 2025	Common Stock	6,963		Direct	F2, F3

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

Explanation of Responses:

Id	Content
F1	Includes 77.194, 66.44, and 72.7280 shares acquired on April 10, 2025, July 10, 2025, and October 10, 2025, respectively, pursuant to the Community Financial System, Inc. Dividend Reinvestment Plan.
F2	The reporting person has received deferred stock units under the Community Financial System, Inc. 2022 Long-Term Incentive Plan, as amended (the "Plan"). Each phantom stock unit which represents a deferred stock unit is the economic equivalent of one share of Community Financial System, Inc. common stock and will be settled in common stock at a predetermined date.
F3	Includes 35.9672, 40.8617, and 45.1866 units of phantom stock acquired as dividend equivalents on April 10, 2025, July 10, 2025, and October 10, 2025, respectively, under the Plan.
F4	Each unit of phantom stock is the economic equivalent of one share of Community Financial System, Inc. common stock. The units of phantom stock relating to the Deferred Compensation Plan will be settled in Community Financial System, Inc. common stock at future dates selected by the reporting person.
F5	Includes 66.2494 and 75.0594 units of phantom stock acquired as dividend equivalents on July 10, 2025, and October 10, 2025, respectively, under the Deferred Compensation Plan.