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,

Key Takeaways Shares of UnitedHealth Group sank Friday following a report that the U.S. Department of Justice is investigating the company's diagnosing practices.The Wall Street Journal reported that the DOJ is probing whether the company tends to over-diagnose conditions that can earn larger Medicare Advantage payouts.

The U.S. Justice Department is investigating UnitedHealth's Medicare billing practices, the Wall Street Journal reported on Friday, while the health insurer said it was unaware of any new probe underway.