Costco Wholesale — Dec 13, 2023 release

Exhibit 99.1 Press Release COSTCO WHOLESALE CORPORATION REPORTS FIRST QUARTER FISCAL YEAR 2024 OPERATING RESULTS AND ANNOUNCES A SPECIAL CASH DIVIDEND OF $15 PER SHARE ISSAQUAH, Wash., December 14, 2023 - Costco Wholesale Corporation (“Costco” or the “Company”) (Nasdaq: COST) today announced its operating results for the first quarter (twelve weeks) of fiscal 2024, ended November 26, 2023. For the first quarter the Company reported net sales of $56.72 billion, an increase of 6.1 percent from $53.44 billion for the first quarter of fiscal year 2023, ended November 20, 2022. Net sales were benefited by approximately one-half to one percent in the U.S. and worldwide from the shift of the fiscal calendar, as a result of the fifty-third week in fiscal year 2023. The following comparable sales reflect comparable locations year-over-year and comparable retail weeks. Comparable sales for the twelve weeks ended November 26, 2023 were as follows: 12 Weeks 12 Weeks Adjusted* U.S. 2.0% 2.6% Canada 6.4% 8.2% Other International 11.2% 7.1% Total Company 3.8% 3.9% E-commerce 6.3% 6.1% *Excluding impacts from changes in gasoline prices and foreign exchange. Net income for the quarter was $1,589 million, $3.58 per diluted share, compared to $1,364 million, $3.07 per diluted share, last year. This year's results included a tax benefit of $44 million, $0.10 per di