UnitedHealth Group says it is cooperating with federal criminal and civil investigations involving its market-leading Medicare business. The health care giant said Thursday that it had contacted the Department of Justice after reviewing media reports about investigations into certain elements of its business.

UnitedHealth Group confirmed Thursday the company is facing criminal and civil investigations from the Department of Justice (DOJ) related to its Medicare billing practices. The health care giant said in a securities filing and subsequent statement it has begun complying with formal criminal and civil requests.