27. Carl Icahn
Icahn has been reshaping corporate America for decades, but his recent efforts to shake up Washington did not go as well. He advised his friend Donald Trump on issues involving regulatory overhaul during the first months of his presidency but left the post amid a conflict-of-interest controversy that he denied. He is currently battling back from a slump that saw his investment fund lose money for 3 straight years. Icahn has lately been hedging his portfolio, convinced the stock market is headed for trouble. Pushed into medical school by his mother, he dropped out because he hated it.