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