#20. Costco Wholesale Corp (COST) — 412.7 BILLION

Costco Wholesale Corporation operates membership warehouses and e-commerce websites. Co. operates 861 warehouses, including 591 in the U.S. and Puerto Rico, 107 in Canada, 40 in Mexico, 33 in Japan, 29 in the United Kingdom, 18 in Korea, 15 in Australia, 14 in Taiwan, five in China, four in Spain, two in France, and one each in Iceland, New Zealand and Sweden. It also operates e-commerce sites in the U.S., Canada, the United Kingdom, Mexico, Korea, Taiwan, Japan and Australia. It provides a wide selection of merchandise, convenience of specialty departments and exclusive member services.