Sam’s Club is a division of Wal-Mart Stores, Inc. . The first Sam’s Club opened its doors in Midwest City, Oklahoma in 1983. Today, Sam’s Club serves more than 47 million U.S. members with locations nationwide, and in Brazil, Canada, China, Mexico and Puerto Rico.

http://www.samsclub.com/ 

Costco currently operates 538 warehouses, including 393 in the United States and Puerto Rico, 75 in Canada, 20 in the United Kingdom, six in Korea, five in Taiwan, eight in Japan and 31 in Mexico. Costco plans to open an additional six new warehouses (including the relocation of one warehouse to a larger and better-located facility) prior to the end of its 2008 fiscal year on August 31, 2008.

BJ's introduced the wholesale club concept to New England in 1984, and has since expanded to become a leading warehouse chain in the eastern United States. The Company currently operates 178 BJ's Wholesale Clubs in 16 states.

http://www.bjs.com/