Wal-Mart Stores, Inc. (NYSE: WMT) is an American public corporation that runs a chain of large, discount department stores. It is the world's largest public corporation by revenue, according to the 2007 Fortune Global 500.[4] Founded by Sam Walton in 1962, it was incorporated on October 31, 1969, and listed on the New York Stock Exchange in 1972. It is the largest private employer in the world and the fourth largest utility or commercial employer, trailing the British National Health Service, and the Indian Railways. Wal-Mart is the largest grocery retailer in the United States, with an estimated 20% of the retail grocery and consumables business, as well as the largest toy seller in the U.S. Wal-Mart also owns and operates the North American company of Sam's Club.