278. Thomas Siebel
When Siebel set out to raise capital for his latest startup, “the understanding was the company would be successful or I would die trying,” he says. Today private investors value his Internet of Things software company, C3IOT, at $1.4 billion. Once apparently Larry Ellison’s (No. 5) top salesman at Oracle, he left to start software firm Siebel Systems in 1990, then sold it to his former employer 16 years later for $5.8 billion in stock and cash. He is a true survivor—having lived through an attack by a rogue elephant on an African safari.