Costco Wholesale CorporationCOST continues to impress investors with positive comparable-store sales (comps) for the fourth month in a row. Excluding the impact of foreign currency fluctuations and gasoline prices, Costco's comps for the month under review rose 3%. Costco currently operates 723 warehouses, which include 506 in the U.S. and Puerto Rico, 94 in Canada, 36 in Mexico, 28 in U.K., 25 in Japan, 12 in Korea, 12 in Taiwan, eight in Australia and two in Spain.