KRISTEN A. HAMNER - 03 Mar 2026 Form 4 Insider Report for CALIFORNIA WATER SERVICE GROUP (CWT)

Role: VP, Chief Human Resource Offcr
Signature: By: /s/ Michelle R. Mortensen For: Kristan Hamner
Issuer symbol: CWT
Transactions as of: 03 Mar 2026
Net transactions value: $0
Form type: 4
Filing time: 05 Mar 2026, 20:03:13 UTC
Previous filing: 05 Mar 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
HAMNER KRISTAN A	VP, Chief Human Resource Offcr	1720 NORTH FIRST STREET, SAN JOSE	By: /s/ Michelle R. Mortensen For: Kristan Hamner	05 Mar 2026	0002058905

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	CWT	Common Stock	Award		+1,650	+111%	$0.000000^*	3,133	03 Mar 2026	Direct	F1, F2
transaction	CWT	Common Stock	Tax liability		-190	-6.1%	$46.99^*	2,943	04 Mar 2026	Direct	F3

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

Explanation of Responses:

Id	Content
F1	Restricted stock granted on 3/3/2026 pursuant to the California Water Service Group equity incentive plan in a transaction exempt under Rule 16-b-3 vests with one-third on March 3, 2027, and with the remaining 2/3 vesting quarterly over the succeeding 24 months.
F2	Includes shares acquired through the Employee Stock Purchase Program.
F3	Represents the number of shares withheld and surrendered to the issuer to satisfy the tax withholding obligations that arose in connection with the vesting of Restricted Stock (RSA) Award granted on March 4,2025