The 400 richest Americans, including U.S. citizens now living abroad, as compiled by Forbes magazine. Following each name is the person's age, net worth, hometown and source of wealth.

Where more than one name is listed under a number, there is a tie.

1. William Gates III, 51, $59 billion, Medina, Wash., Microsoft

2. Warren Buffett, 77, $52 billion, Omaha, Neb., Berkshire Hathaway

3. Sheldon Adelson, 74, $28 billion, Las Vegas, casinos, hotels

4. Lawrence Ellison, 63, $26 billion, Redwood City, Calif., Oracle

5. Sergey Brin, 34, $18.5 billion, Palo Alto, Calif., Google

5. Larry Page, 34, $18.5 billion, San Francisco, Google

7. Kirk Kerkorian, 90, $18 billion, Los Angeles, investments, casinos

8. Michael Dell, 42, $17.2 billion, Austin, Texas, Dell

9. Charles Koch, 71, $17 billion, Wichita, Kan., oil, commodities

9. David Koch, 67, $17 billion, New York, oil, commodities

11. Paul Allen, 54, $16.8 billion, Mercer Island, Wash., Microsoft, investments

12. Christy Walton and family, 52, $16.3 billion, Jackson, Wyo., Wal-Mart inheritance

12. Jim Walton, 59, $16.3 billion, Bentonville, Ark., Wal-Mart

12. S. Robson Walton, 63, $16.3 billion, Bentonville, Ark., Wal-Mart

15. Alice Walton, 58, $16.1 billion, Fort Worth, Texas, Wal-Mart

16. Steven Ballmer, 51, $15.2 billion, Hunts Point, Wash., Microsoft

17. Abigail Johnson, 45, $15 billion, Boston, Fidelity