X0508 4 2024-10-22 0000909832 COSTCO WHOLESALE CORP /NEW COST 0001852700 POLIT JAVIER 999 LAKE DRIVE ISSAQUAH WA 98027 1 Executive Vice President 0 Common Stock 2024-10-22 4 A 0 6737.124 0 A 10420.248 D Common Stock 2024-10-22 4 F 0 380.176 893.49 D 10040.072 D Common Stock 2024-10-22 4 F 0 293.891 893.49 D 9746.181 D Grant was initially made on October 22, 2023 subject to performance conditions concerning fiscal 2024, which have been deemed satisfied by the Compensation Committee of the Board of Directors. The earned awards vest 20% on the first anniversary of the grant date and an additional 20% vest over each of the ensuing four years based on continued employment with the Company. Not applicable. Grant of Restricted Stock Units. This transaction is a withholding by the Company for taxes in connection with the vesting of previously granted restricted stock units. The price represents the closing market price of Costco common stock on Nasdaq on October 22, 2024. /s/ Alejandro Torres, Attorney-in-Fact 2024-10-24