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. It was founded by Sam Walton in 1962, 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 People's Liberation Army of China, the National Health Service of the United Kingdom, 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., with an estimated 22% share of the toy market. Wal-Mart operates in Mexico as Walmex, in the United Kingdom as ASDA, and in Japan as Seiyu. It has wholly-owned operations in Argentina, Brazil, Canada, Puerto Rico, and the UK.