The Justice Department launched an antitrust investigation into UnitedHealth Group, owner of the nation's biggest health insurer, a leading manager of drug benefits and a sprawling network of doctor groups.

The Justice Department launched an antitrust investigation into UnitedHealth Group, owner of the nation’s biggest health insurer, a leading manager of drug benefits and a sprawling network of doctor groups.

The Justice Department launched an antitrust investigation into UnitedHealth Group, owner of the nation’s biggest health insurer, a leading manager of drug benefits and a sprawling network of doctor groups.