U.S. Billionaires

. Bill Gates

Net Worth: $67 billion

Source of wealth: Microsoft

.  Warren Buffett

Net worth: $53.5 billion

Source of wealth: Berkshire Hathaway

.  Larry Ellison

Net worth: $43 billion

Source of wealth: Oracle

.  Charles Koch

Net worth: $34 billion

Source of wealth: diversified

.  David Koch

Net worth: $34 billion

Source of wealth: diversified

.  Christy Walton & family

Net worth: $28.2 billion

Source of wealth: Wal-Mart

.  Michael Bloomberg

Net worth: $27 billion

Source of wealth: Bloomberg LP

.  Jim Walton

Net worth: $26.7 billion

Source of wealth: Wal-Mart

.  Sheldon Adelson

Net worth: $26.5 billion

Source of wealth: casinos

. Alice Walton

Net worth: $26.3 billion

Source of wealth: Wal-Mart

. S. Robson Walton

Net worth: $26.1 billion

Source of wealth: Wal-Mart

. Jeff Bezos

Net worth: $25.2 billion

Source of wealth: Amazon.com

. Larry Page

Net worth: $23 billion