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.

May 13 (UPI) -- UnitedHealth Group announced Tuesday CEO Andrew Witty will step down, citing "personal reasons." Witty will leave the role of CEO and be replaced by Stephen J. Hemsley, effective immediately.

UnitedHealth Group's stock has plunged nearly 50% due to the CEO resignation, withdrawal of guidance, and ongoing legal issues, creating a potential buying opportunity. The stock is deeply oversold with an RSI of 15, trading below both the 200-day and 50-day moving averages, indicating capitulation.

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 CEO Andrew Witty is stepping down from his post for personal reasons and the health care giant says it’s suspending its full-year forecast due to higher-than-expected medical costs.

UnitedHealth Group Chief Executive Officer Andrew Witty stepped down, effective immediately, "for personal reasons", the company said Tuesday. “Leading the people of UnitedHealth Group has been a tremendous honor as they work every day to improve the health system, and they will continue to inspire me,” Witty said in a statement shared by UHG.

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