X0306 4 2023-03-03 0001035201 CALIFORNIA WATER SERVICE GROUP CWT 0001629473 Mortensen Michelle R 1720 NORTH FIRST STREET SAN JOSE CA 95112 1 Corporate Secretary Common Stock 2023-03-03 4 F 0 42 56.84 D 8131 D Common Stock 2023-03-03 4 A 0 1453 0 A 9584 D Common Stock 2023-03-03 4 F 0 856 56.84 D 8728 D Represents the number of shares withheld by and surrendered to the Issuer to satisfy the tax withholding obligations that arose in connection with the vesting of the Restricted Stock (RSA) Award 528. On 3/3/2020, the reporting person was granted a Performance Stock Unit (PSU) of 1453 shares of common stock. The PSU vested in full based on satisfaction of certain performance criteria approved by the Board of Directors. The performance criteria was met resulting in 156% payout of the original goal. Represents the number of shares withheld by and surrendered to the issuer to satisfy the tax withholding obligations that arose in connection with the vesting of the Performance Stock Unit (PSU) Award #543 Michelle R. Mortensen 2023-03-06