Todd Combs
Company: Berkshire Hathaway
Current CEO: Warren Buffett
No one will ever be able to replace Warren Buffett, but someone will have to succeed him. Berkshire Hathaway will likely split up Buffett's duties when he is no longer CEO, with two different people splitting the responsibilities -- one running the company, the other investments. The second of those could be Todd Combs, the little-known hedge fund manager who was propelled to stardom last year when he was hired at Berkshire. He is the only known contender to eventually take over the investing piece of Buffett's duties, though the promotion is hardly in the bag. Fortune has reported that Combs' current position is being viewed as an "extended trial." Will he succeed? Who knows. It may seem like the Oracle of Omaha is betting on it, but then again, he has no plans to retire.