Costco's sales at stores open at least a year rose 6 percent in June, beating Wall Street's estimates.
Analysts surveyed by Thomson Reuters expected a 5.3 percent increase.
This figure is a key gauge of a retailer's health because it excludes results from stores recently opened or closed.
Costco Wholesale Corp. said Thursday that sales at U.S. locations open at least a year climbed 6 percent. Internationally, the metric rose 7 percent.
Excluding higher gasoline prices and foreign currency fluctuations, sales at stores open at least a year increased 6 percent for the total company and for U.S. stores. Overseas, the figure rose 8 percent.
Total revenue for the five weeks ended July 6 climbed 10 percent to $10.89 billion.
For the year to date, the Issaquah, Washington company's sales at stores open at least a year increased 4 percent. The figure climbed 5 percent in the U.S. and 2 percent abroad.
Excluding higher gasoline prices and foreign currency fluctuations, sales at stores open at least a year rose 6 percent for the total company. In the U.S. the metric increased 5 percent. It climbed 7 percent overseas.
Total revenue for the year to date increased 7 percent to $92.88 billion.
Costco currently runs 658 warehouses, including 465 in the U.S. and Puerto Rico, 87 in Canada, 33 in Mexico, 25 in the U.K., 20 in Japan, 11 in Korea, 10 in Taiwan, six in Australia and one in Spain. The company plans to open up to an additional five new warehouses before its fiscal year ends on Aug. 31.