Rank: 1
Net worth: $59 billion
Age: 55
Source of wealth: Microsoft (MSFT)
(Microsoft publishes MSN Money)
(Microsoft publishes MSN Money)
Residence: Medina, Wash.
Rank: 2
Net worth: $39 billion
Age: 81
Source of wealth: Berkshire Hathaway
Residence: Omaha, Neb.
Rank: 3
Net worth: $33 billion
Age: 67
Source of wealth: Oracle (ORCL)
Residence: Redwood City, Calif.
Rank: 4
Net worth: $25 billion
Age: 75
Source of wealth: Koch Industries (manufacturing)
Residence: Wichita, Kan.
Rank: 5
Net worth: $25 billion
Age: 71
Source of wealth: Koch Industries
Residence: New York City
Rank: 6
Net worth: $24.5 billion
Age: 56
Source of wealth: Wal-Mart Stores (WMT)
Residence: Jackson, Wyo.
Rank: 7
Net worth: $22 billion
Age: 81
Source of wealth: Hedge funds
Residence: Katonah, N.Y.
Rank: 8
Net worth: $21.5 billion
Age: 78
Source of wealth: Casinos
Residence: Las Vegas
Rank: 9
Net worth: $21.1 billion
Age: 63
Source of wealth: Wal-Mart
Residence: Bentonville, Ark.
Rank: 10
Net worth: $20.9 billion
Age: 61
Source of wealth: Wal-Mart
Residence: Millsap, Texas