Costco Wholesale Corp New (COST) SEC Filing 10-K Annual report for the fiscal year ending Sunday, August 30, 2015

Exhibit 99.1

COSTCO WHOLESALE CORPORATION REPORTS FOURTH QUARTER AND

FISCAL YEAR 2015 OPERATING RESULTS

ISSAQUAH, Wash., September 29, 2015 – Costco Wholesale Corporation (“Costco” or the “Company”) (Nasdaq: COST) today announced its operating results for the 16-week fourth quarter and the 52-week fiscal year ended August 30, 2015.

Net sales for the fourth quarter were $34.99 billion, an increase of one percent from $34.75 billion in fiscal 2014. Net sales for the fiscal year were $113.67 billion, an increase of three percent from $110.21 billion last year.

Comparable sales were as follows:

Comparable sales for these periods excluding the negative impacts from gasoline price deflation and foreign exchange were as follows:

Net income for the fourth quarter was $767 million, or $1.73 per diluted share, compared to $697 million, or $1.58 per diluted share, last year.

Net income for this fiscal year was $2.38 billion, or $5.37 per diluted share, compared to $2.06 billion, or $4.65 per diluted share, last year. Net income this year was positively impacted by a $57 million ($.13 per diluted share) tax benefit in connection with a second-quarter special cash dividend received by the Company 401(k) plan participants.

Costco currently operates 686 warehouses, including 480 in the United States and Puerto Rico, 89 in Canada, 36 in Mexico, 27 in the United Kingdom, 23 in Japan, 12 in Korea, 11 in Taiwan, seven in Australia and one in Spain. The Company plans to open up to an additional 12 new warehouses (including one relocation) before the end of calendar year 2015. Costco also operates e-commerce web sites in the U.S., Canada, the United Kingdom and Mexico.