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

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.

UnitedHealth Group is being investigated by the Justice Department for possible criminal Medicare fraud, The Wall Street Journal reported, citing people familiar with the matter. The healthcare-fraud unit of the Justice Department's criminal division is overseeing the investigation,

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