Stephen Hemsley hasn’t been CEO at UnitedHealth Group in nearly a decade yet he’s never really left. Hemsley, 72, has remained chairman and a major shareholder in the health care behemoth — and now is back in the CEO suite and is expected to reinstate his brand of operational and financial discipline that turbocharged the company’s growth.

Stephen Hemsley ran UnitedHealth Group for more than a decade. It's a different company after four years with Andrew Witty in charge.

Former CEO and current chairman Stephen Hemsley is stepping back into the top job following the abrupt resignation of Andrew Witty, UnitedHealth said.

UnitedHealth Group Chairman Stephen Hemsley is returning to helm the health care conglomerate once again. He will replace Andrew Witty effective immediately.

UnitedHealth CEO Andrew Witty is stepping down for personal reasons and the nation's largest health insurer suspended its full-year financial outlook due to higher-than-expected medical costs. Chairman Stephen Hemsley will become CEO, effective immediately, the Minnesota company said.

UnitedHealth's stock has plunged nearly 40% year-to-date as the company has battled a series of crises. Can the healthcare giant turn it around? Seeking Alpha analysts weigh in.

British boss of US healthcare giant UnitedHealth quits for ‘personal reasons’ - The move comes five months after one of the company’s top executives was killed after being shot as he walked to an investor conference in New York.