Andrew Mason

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Andrew Mason

Age: 32

Occupation: CEO, Groupon

When news that your board didn't fire you causes your company's share price to fall still farther, you're a clout-challenged CEO indeed. Many blame Mason for Groupon's transformation from white-hot IPO to Wall Street whipping boy; 2013 will be his make-or-break year.

Update (February 28): Mason was fired from Groupon.

Photograph: SHAUNA BITTLE/CHICAGO TRIBUNE