Robert Duggan

Robert Duggan knew nothing about running a biotech firm when he invested in cancer drug maker Pharmacyclics in 2004. But having lost a son to brain cancer, he was passionate about the industry. Four years later, after the company's board resigned en masse in favor of his slate, Duggan took over as CEO and by 2013 he was a billionaire thanks to the surprising success of Imbruvica, a potent treatment for chronic lymphocytic leukemia that continues to buoy Pharmacyclics' stock. Duggan's enthusiasm for investing began four decades earlier in a corporate finance class he took at University of California at Santa Barbara. Before striking it big with Pharmacyclics, he invested in tech companies, a cookie bakery and a pioneering robotic surgery company. Duggan is a top donor to the Church of Scientology, of which he is a member.