The Department of Justice Thursday (July 21) formally filed suit to block the two pending health insurance mergers, partially due to the risk of reduced competition in the exchanges, and sent a strong signal that the key players would have little recourse but to challenge the move in court. Aetna, which has been working on a $37 billion acquisition of Humana, and Anthem, which placed a $54 billion bid for Cigna, immediately said they would fight back. DOJ found that...