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

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

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

Former UnitedHealth Group chief executive officer Stephen Hemsley to replace Andrew Witty. Here's what we know.

UnitedHealth Group announced that CEO Andrew Witty is stepping down due to 'personal reasons,' Stephen Hemsley will replace him.

Shares of UnitedHealth Group plunged more than 18% following a report that the Department of Justice is carrying out a criminal investigation into the health-care giant over possible Medicare fraud.

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.

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.