Four of the Ten richest Americans are heirs of the Wal-Mart fortune who live in Bentonville, and a fifth is another member of the Walton family living in Texas. Sam Walton`s widow Helen and their children Alice, Jim, John and S- Robson Walton are worth 18 billion dollars each. Alice Walton lives in Fort Worth, Texas, while the rest live in Bentonville. The five Walton`s shared the fourth richest slot on a list compiled by Forbes magazine. There are now 313 U-S billionaires, nearly 20 percent more than last year. Microsoft chairman Bill Gates is still at the top of the list with a net worth of 48 billion dollars. Other Arkansans worth over a billion dollars are investment banker Jack Stephens of Little Rock and his family, who are worth One and a half billion; and Lieutenant Governor Win Rockefeller of Morrilton, whose share of the Standard Oil fortune gives him a net worth of 1.2 billion dollars. Don Tyson of Tyson Foods in Springdale was also among the 400 richest Americans, but fell shy of the illion mark with 925 million dollars.