Bylaw Amendment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 16, 2024 COSTCO WHOLESALE CORPORATION (Exact name of registrant as specified in its charter) Washington 0-20355 91-1223280 (State or other jurisdiction of incorporation) (Commission File No.) (I.R.S. Employer Identification No.) 999 Lake Drive Issaquah , WA 98027 (Address of principal executive offices and zip code) Registrant’s telephone number, including area code: 425 - 313-8100 Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below): ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Title of each class Trading Symbol(s) Name of each exchange on which registered Common Stock, par value $.005 per share COST NASDAQ Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐ Item 5.03.     Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year. The Board of Directors of Costco Wholesale Corporation amended and restated the Company's Bylaws, effective September 16, 2024. The amendments implement a cure process for certain deficiencies in director nomination notices submitted by shareholders. For nomination notices received by the Company within the time period specified in the Bylaws, the Company will notify shareholders of deficiencies in the notice and there will be an opportunity to cure such deficiencies within the time period specified. The foregoing description of the amendments is not complete and is qualified in its entirety by reference to the text of the Bylaws, as amended, a copy of which is filed as Exhibit 3.2 to this Current Report on Form 8-K. Item 9.01.     Financial Statements and Exhibits (d) Exhibits. 3.2.     Bylaws as amended of Costco Wholesale Corporation 104.    Cover Page Interactive Data File (embedded within the Inline XBRL document). SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized. COSTCO WHOLESALE CORPORATION Dated: September 19, 2024 By: /s/ John Sullivan John Sullivan Executive Vice President, General Counsel and Secretary