U.S. DOJ and plaintiff states sued to block the merger of two of the country’s largest health insurers. According to the complaint, alleges that their merger would substantially reduce Medicare Advantage competition in more than 350 counties in 21 states, affecting more than 1.5 million Medicare Advantage customers in those counties. Before seeking to acquire Humana, Aetna had pursued aggressive expansion in Medicare Advantage. Aetna, the nation’s fourth-largest Medicare Advantage insurer by membership, has nearly doubled its Medicare Advantage footprint over the past four years. Humana is the nation’s second-largest Medicare Advantage insurer by membership. The lawsuit also alleges that Aetna’s purchase of Humana would substantially reduce competition to sell commercial health insurance to individuals and families on the public exchanges in 17 counties in Florida, Georgia and Missouri, affecting more than 700,000 people in those counties. The lawsuit alleges that by buying Humana, Aetna would eliminate one of its strongest and most capable competitors in these markets. The district court granted the injunction, rejecting the parties arguments that the Medicare Advantage and Medicare programs were competing products that constrained one another’s prices, and noting that Aetna’s exit from several markets, allegedly because of the Affordable Care Act, appeared to be designed to eliminate a problem with the merger, rather than being an unrelated business decision.