X0508 4 2024-10-22 0000909832 COSTCO WHOLESALE CORP /NEW COST 0001928633 Frates Caton 999 LAKE DRIVE ISSAQUAH WA 98027 1 Executive Vice President 0 Common Stock 2024-10-22 4 F 0 190.892 893.49 D 9491.403 D Common Stock 2024-10-22 4 F 0 157.357 893.49 D 9334.046 D Common Stock 2024-10-22 4 F 0 125.37 893.49 D 9208.676 D Common Stock 2024-10-22 4 F 0 255.382 893.49 D 8953.294 D Common Stock 2024-10-22 4 F 0 227.522 893.49 D 8725.772 D 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