Wal-Mart heir; Chairman, Crystal Bridges Museum of American Art
Age: 67
Net worth: $33.8 billion
Amancio Ortega
Co-founder, Zara
Age: 81
Net worth: $71.3 billion
Bernard Arnault
Chairman and CEO, Louis Vuitton
Bill Gates
Co-founder, Microsoft
Age: 60
Net worth: $86 billion
Gates has held the No. 1 spot as the world's richest person for four years in a row, and for 18 out of the past 23 years.
Carlos Slim Helu
Chairman, América Móvil
Age: 77
Net worth: $54.5 billion
Charles Koch
CEO, Koch Industries
Age: 81
Net worth: $48.3 billion
