10. David Hains

•  Net Worth: $2.3 B                                                                      
•  Source of Wealth: finance
•  Citizen: Australia
•  Age: 82

David Hains owns one of Australia's biggest and most private hedge funds, Portland House Group, based in his hometown of Melbourne. He later became well-known for restructuring companies like U.S. steelmaker Wheeling-Pittsburgh. He is also an active horse breeder and racer though his Kingston Park Stud.