X0508 4 2024-10-24 0000909832 COSTCO WHOLESALE CORP /NEW COST 0001184493 GALANTI RICHARD A 999 LAKE DRIVE ISSAQUAH WA 98027 1 1 Executive Vice President 0 Common Stock 2024-10-24 4 S 0 1416.461 894.6802 D 27400 D Common Stock 726 I By Spouse Common Stock 7000 I North Island Holdings LLC The price shown is a weighted average price for shares sold in multiple transactions; the sale prices ranged from $894.240 to $894.710 per share. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The shares are held by an LLC of which the reporting person is the managing member. The reporting person disclaims beneficial ownership of these securities. /s/ Alejandro Torres, Attorney-in-Fact 2024-10-24