UnitedHealth Group (UNH) shares dropped 7% Friday to lead 澳洲幸运5官方开奖结果体彩网:Dow Jones Industrial Average decliners following a report that the U.S. Department of Justice is investigating the healthcare giant's Medicare billing practices.

According to The Wall Street Journal, the DOJ is investigating whether UnitedHealth tends to over-diagnose conditions that can earn it extra payouts from the 澳洲幸运5官方开奖结果体彩网:Medicare Advantage program. The newspaper had reported on allegations of the practice in December, ✱with doctors telling the oꦺutlet they were trained to "document revenue-generating diagnoses, including some they felt were obscure or irrelevant."

UnitedHealth Has Said WSJ 'Does Not Understand' Medicare Advantage Program

UnitedHealth on Friday reiterated some of its previous criticisms of the Journal's reporting on 澳洲幸运5官方开奖结果体彩网:Medicare Advantage, calling it "misinformation." The company said that "any suggestion that our practices are fraudulent is outrageous and false."

"We are not aware of the 'launch' of any 'new' activity as reported by the Journal," UnitedHealth said. "We are aware, however, that the Journal has engaged in a year-long campaign to defend a legacy system that rewards volume over keeping patients healthy and addressing their underlying conditions."

The DOJ declined to comment on the report.

The news was also weighing on other health insurer stocks Friday, with CVS Health (CVS) and Humana (HUM) trading lower following the report. UnitedHealth shares were down roughly 7% Friday afternoon at $466.77, their lowest level since last April.

UPDATE—This article has been updated with the latest share price information and a response from the Department of Justice.