He is followed by Berkshire Hathaway Inc.'s Warren Buffett (No. 2) with $46 billion, also up $7 billion from last year, and Oracle Corp's Larry Ellison (No. 3) with $41 billion, up $8 billion - and the biggest dollar gainer this year.
Facebook founder Mark Zuckerberg has been pushed down in the rankings to the no. 36 spot with his estimated net worth falling by about $8 billion to $9.4 billion since Facebook went public in May.