Mexican billionaire Carlos Slim Helu tops the Forbes' world's richest list for a fourth year in a row. Find out what other billionaires topped this year's list.
15. Sheldon Adelson -- An American casino and hotel magnate, Adelson is Chairman and Chief Executive Officer of the Las Vegas Sands Corporation. He is worth an estimated $26.5 billion.
14. Jim Walton (Right, pictured with brother Rob and sister Alice) -- The youngest son of Walmart founder Sam Walton, Jim Walton is also the chairman and CEO of Arvest Bank. He's worth an estimated $26.7 billion.
13. Michael Bloomberg -- The mayor of New York City is worth an estimated $27 billion.
12. Stefan Persson -- The Sweden native is chairman of the retailer H & M and is worth an estimated $28 billion.
11. Christy Walton & Family -- The WalMart heiress is the world's richest woman, worth an estimated $28.2 billion.
10. Bernard Arnault -- The chairman of the French luxury goods group LVMH is worth an estimated $29 billion.
9. Liliane Bettencourt -- The French billionaire and L'Oreal heiress is worth an estimated $30 billion.
8. Li Ka-shing -- The Hong Kong tycoon is chairman of Hutchison Whampoa & Chueng Kong Holdings. He's worth an estimated $31 billion.
6. Charles Koch (tie) -- Along with brother David, Charles is co-owner and executive vice president of Koch Industries, the second-largest privately held company in the U.S. He's worth an estimated $43 billion.
6. David Koch (tie) -- The billionaire is co-owner (with older brother Charles) and an executive vice president of Koch Industries, a conglomerate that is the second-largest privately held company in the U.S. He's worth an estimated $34 billion.
5. Larry Ellison -- The CEO of Oracle, Ellison's net worth is estimated at $43 billion.
4. Warren Buffett -- The 82-year-old CEO of Berkshire Hathaway is worth an estimated $53.5 billion.
3. Armancio Ortega -- The Spanish Inditex chairman is worth an estimated $57 billion.
2. Bill Gates -- Gates, chairman and co-founder of Microsoft Corp., is also co-chairman of the Bill & Melinda Gates Foundation. His net worth is more than $67 billion.
1. Carlos Slim Helu & Family -- The world's richest person for a third year in a row, the Mexican telecom mogul increased his new worth to more than $73 billion.