288. William Wrigley Jr.
$2.8 billion # self-made score: source: chewing GUM
age: 54 residence: north Palm beach, fla. B.a., duke ’85 The candy heir sold his family’s chewing gum and candy business to Mars for $23 billion in 2008. A scuba-diving enthusiast, Wrigley has spent much of his time in recent years promoting marine conservation and managing his family’s investments.