Malone Mitchell

Mitchell started acquiring west Texas and Colorado oil and gas properties in 1985. Partnered with Exxon, Chevron, BP. In 2006 sold controlling stake in Riata Energy to one-time billionaire Tom Ward, co-founder of Chesapeake Energy, for $500 million. Mitchell and Ward renamed the company SandRidge and in late 2006 bought billionaire Carl Icahn's National Energy Group for $1.5 billion. Mitchell sold the rest of his shares in 2007. Now he's looking to redeploy his cash horde overseas through pipsqueak publicly traded TransAtlantic Petroleum. Has bought up acreage in oil and gas spots like Turkey, Morocco and Romania, with hopes of using his team's eye for geology and new-fangled drilling skills to unlock vast reserves. Spent 150 days in Turkey in the past year. Risk: it ain't Texas. With wife, Amy, last year donated $57 million to alma mater Oklahoma State to fund entrepreneur program; school's second-biggest giver behind T. Boone Pickens.