UnitedHealth Group stock fell sharply Friday following a report that said the Justice Department had launched a civil fraud investigation into the company’s Medicare billing practices.The DOJ probe aims to examine the healthcare company’s practices for documenting diagnoses that trigger extra payments to its Medicare Advantage plans,

The new civil fraud investigation is examining UnitedHealth's practices for recording diagnoses that trigger extra payments to its Medicare Advantage plans, including at physician groups the insurance giant owns, the report added. DoJ and UnitedHealth did not immediately respond to a Reuters request for comment.