UnitedHealth Group called The Wall Street Journal's report "misinformation" and said it was unaware of reported investigaiton.

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.

Any suggestion that our practices are fraudulent is outrageous and false," the insurer said.