Loretta E. Lynch.
WASHINGTON—The U.S. Department of Justice and attorneys general from multiple states and the District of Columbia sued yesterday to block Anthem’s proposed acquisition of Cigna and Aetna’s proposed acquisition of Humana, alleging that the transactions would increase concentration and harm competition across the country, reducing from five to three the number of large, national health insurers in the nation.

The department and state attorneys general filed these two merger challenges in the U.S. District Court for the District of Columbia. The complaints allege that the two mergers—valued at $54 billion and $37 billion—would harm seniors, working families, individuals, employers, doctors and other health care providers by limiting price competition, reducing benefits, decreasing incentives to provide innovative wellness programs and lowering the quality of care.

“Competitive insurance markets are essential to providing Americans the affordable and high-quality health care they deserve,” said attorney general Loretta E. Lynch in a statement issued by the Department of Justice. “These mergers would restrict competition for health insurance products sold in markets across the country and would give tremendous power over the nation’s health insurance industry to just three large companies. Our actions seek to preserve competition that keeps premiums down and drives insurers to collaborate with doctors and hospitals to provide better health care for all Americans.”