Chairman and CEO, Exxon Mobil
Tillerson claimed earlier this year that natural gas producers -- Exxon (Fortune 500) is the U.S.'s largest -- were "losing our shirts" due to the commodity's depressed prices. But Exxon, No. 1 on the , Fortune 500, has alternatives: the company has been shifting rigs to oil fields and bolstering its financial performance (and outlook) with key acquisitions and divestitures. It doubled its stake in North Dakota's booming Bakken shale, invested in methane gas production in Australia, and formalized a partnership with Russian oil giant OAO Rosneft that will grant the company access to the untapped Russian Arctic. --Erika Fry
He's a pro-customer, tightfisted risk-taker who is conditioning Wall Street to embrace his erratic earnings. If you're running a business with high margins - watch out.