Costco Wholesale Corporation is filing this Amendment to its Current Report on Form 8-K filed on August 17, 2023, which reported that the Board of Directors elected Helena Buonanno Foulkes as a director effective August 16, 2023. At the time of her election, she was not appointed to serve as a member of any committees of the Board. On January 18, 2024, the Board appointed Ms. Foulkes to the Audit Committee and the Nominating and Governance Committee.