UnitedHealth (UNH) stock was down Friday on a report from The Wall Street Journal that the health insurance company faces a Department of

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.

Shares of UnitedHealth Group (NYSE:UNH) dropped ~7% in the premarket on Friday after The Wall Street Journal reported that the U.S. Department of Justice ((DoJ)) has launched a new investigation into the company’s business practices.