UnitedHealth Group saw its share price fall on Friday after the Wall Street Journal reported that it was facing a DOJ investigation.

The Wall Street Journal says the Justice Department in recent months has launched a new investigation into UnitedHealth Group’s billing practices as a civil fraud investigation looks at the use of diagnosis data to trigger extra payments to the company’s Medicare Advantage plans.

The US Justice Department is investigating UnitedHealth Group’s Medicare billing practices, Bloomberg reported, citing a person familiar with the matter.