UnitedHealth Group Inc. has confirmed it is under both civil and criminal investigation by the U.S. Department of Justice concerning its participation in the Medicare program, specifically its Medicare Advantage billing practices. The company proactively reached out to the DOJ following media reports about the probes and is now cooperating with formal requests from the agency. UnitedHealth maintains confidence in its Medicare practices, citing prior audits by the Centers for Medicare & Medicaid Services (CMS) that found its practices accurate, as well as a Special Master review that found no wrongdoing in its Medicare Advantage business. The investigation follows reports alleging that the company pressured doctors to submit diagnoses that increased payments. UnitedHealth’s stock has declined by over 4% in pre-market trading after the announcement. The DOJ investigation disclosure comes amid increased scrutiny of healthcare costs and competition, as well as the recent departure of UnitedHealth’s CEO.