Find out what the 50 richest Americans are worth and where they make their money.
Following is the list as compiled by Forbes magazine. Following each name is the person's age, net worth and source of wealth.
Where more than one name is listed under a number, there is a tie.
1. Bill Gates, 50, $53bn - Microsoft
2. Warren Edward Buffett, 76, $46bn - Berkshire Hathaway
3. Sheldon Adelson, 73, $20.5bn - casinos, hotels
4. Lawrence Joseph Ellison, 62, $19.5bn - Oracle
5. Paul Gardner Allen, 53, $16bn - Microsoft, investments
6. Jim Walton, 58, $15.7bn - Wal-Mart
7. Christy Walton and family, 51, $15.6bn - Wal-Mart
inheritance
7. Robson Walton, 62, $15.6bn - Wal-Mart
9. Michael Dell, 41, $15.5bn - Dell
Alice Walton, 57, $15.5bn - Wal-Mart
11. Helen Walton, 86, $15.3bn - Wal-Mart
12. Sergey Brin, 33, $14.1bn - Google
13. Larry Page, 33, $14bn - Google
14. Jack Crawford Taylor and family, 84, $13.9bn - Enterprise Rent-A-Car
15. Steven Anthony Ballmer, 50, $13.6bn - Microsoft
16. Abigail Johnson, 44, $13bn - Fidelity
17. Barbara Cox Anthony, 83, $12.6bn - Cox Enterprises
Anne Cox Chambers, 86, $12.6bn - Cox Enterprises
19. Charles De Ganahl Koch, 70, $12bn - oil, commodities
19. David Hamilton Koch, 66, $12bn - commodities
21. Forrest Edward Mars Jr, 75, $10.5bn - candy
21. Jacqueline Mars, 67, $10.5bn - candy
21. John Franklyn Mars, 70, $10.5bn - candy
24. Carl Icahn, 70, $9.7bn - leveraged buyouts
25. John Werner Kluge, 92, $9.1bn - Metromedia
26. Kirk Kerkorian, 89, $9bn - investments, casinos
27. Donald Bren, 74, $8.5bn - real estate
27. George Kaiser, 64, $8.5bn - oil and gas, banking
27. George Soros, 76, $8.5bn - hedge funds
30. Philip Knight, 68, $7.9bn - Nike
31. Philip Anschutz, 66, $7.8bn - investments
32. Keith Rupert Murdoch, 75, $7.7bn - News Corp
32. Pierre Omidyar, 39, $7.7bn - eBay
34. Charles Ergen, 53, $7.6bn - EchoStar
35. Dan Duncan, 73, $7.5bn - energy
35. Edward Crosby Johnson III, 76, $7.5bn - Fidelity
35. Sumner Redstone, 83, $7.5bn - Viacom
38. Donald Edward Newhouse, 76, $7.3bn - publishing
38. Samuel Irving Newhouse Jr, 78, $7.3bn - publishing
40. Leonard Blavatnik, 49, $7bn - Access Industries
40. Ronald Owen Perelman, 63, $7bn - leveraged buyouts
42. Eli Broad, 73, $5.8bn - investments
43. Robert Muse Bass, 58, $5.5bn - oil, investments
44. Michael Rubens Bloomberg, 64, $5.3bn - Bloomberg LP
45. John Menard Jr, 66, $5.2bn - home improvement stores
45. Robert Rowling, 53, $5.2bn - oil and gas, investments
45. Eric Schmidt, 51, $5.2bn - Google
48. Micky Arison, 57, $5bn - Carnival Cruises
49. Steven Paul Jobs, 51, $4.9bn - Apple Computer, Pixar
50. David Geffen, 63, $4.6bn - DreamWorks
Charles Schwab, 69, $4.6bn