10. Eduardo Saverin, Facebook, 29, $1.6 billion

Together with former best-friend Mark Zuckerberg, started Facebook at Harvard and received a 30% stake in the company. Relationship soured when Facebook sued Saverin for allegedly interfering with business and insisting on keeping 30% stake. Saverin countersued the case with both parties settling out-side of the courts. The deal saw Saverin apparently receive a 5% stake and a cofounder bio on Facebook's site. According to Forbes.com, Saverin has been selling shares and now holds 2% and has been active in Silicon Start-Up Qwiki.