Yahoo Finance

As CEO for more than a decade, Stephen Hemsley built up UnitedHealth Group now a $400 billion healthcare behemoth. With his return to the top job, the company will learn whether his playbook still works. Hemsley, 72, is back in the chief executive’s chair after seven years as chairman, and UnitedHealth is in a more vulnerable position than it has been since he started his first CEO stint in 2006, in the shadow of a stock-options-backdating scandal that helped lead to the ouster of his predecessor.