UnitedHealth Group’s stock dropped 7.3% after reports revealed a Justice Department investigation into the company’s Medicare billing practices, focusing on how it documents diagnoses that trigger extra payments for its Medicare Advantage plans.

UnitedHealth denied the allegations, calling them “outrageous and false,” and emphasized its compliance with government reviews.

The probe follows scrutiny from the Office of Inspector General for the U.S. Department of Health and Human Services, which flagged potential misuse of diagnoses for risk-adjusted payments, Barron’s has reported.

Despite the investigation, analysts from TD Cowen believe the market’s reaction is overdone, maintaining a “Buy” rating on the stock.

Written by B.C. Begley