According to Thomson Reuter's data, analysts had anticipated the largest U. S. Warehouse Club Operator to post sales of 9.7%.

Helped by gasoline price inflation and strong foreign currencies, Warehouses Operator Costco Wholesale Corp. said that its same-store sales grew 9% for May 201. Comps were also improved by an extra day of sales this year due to the shift in Memorial Day holiday.

Total Company analogous sales augmented 9%, with 7% improvement in the U. S. and 17% growth in international stores, for May 2010. The holiday budge optimistically impacted this year's sales by about 2% overall, and 3% in the U. S.

This compares to a total same-store decline of 7% in May of last year, with 6% fall in the U. S. and 7% drop internationally. Memorial Day holiday fell in the reporting month of May last year, but not this year.

Total comparable sales for May 2010 was up 5%, with an increase of 5% in U. S same-store sales and 9% growth internationally, not including the positive impact of higher gasoline prices and strengthening of foreign currencies.

Prior year month's equivalent store sales was depressingly impacted by deflation of gasoline price and exchange rates, excluding which, total same-store sales improved 1%, with a 1% decline in the U. S offset by a 7% improvement in international stores.

Costco currently operates 568 warehouses, including 414 in the U. S. and Puerto Rico, 78 in Canada, 21 in the U. K., seven in Korea, six in Taiwan, nine in Japan, one in Australia and 32 in Mexico. At the end of May last year, the company operated 555 warehouses, including 407 in the U. S. and Puerto Rico, 77 in Canada, 21 in the U. K., six in Korea, five in Taiwan, eight in Japan and 31 in Mexico.