Judge Amy Berman Jackson for the District of Columbia ruled in favor of the Justice Department in its civil antitrust lawsuit to block health insurer Anthem, Inc.’s acquisition of Cigna Corp., the Justice Department announced.

“Today’s decision is a victory for American consumers,” said Acting Assistant Attorney General Brent Snyder of the Justice Department’s Antitrust Division. “This merger would have stifled competition, harming consumers by increasing health insurance prices and slowing innovation aimed at lowering the costs of healthcare. In concluding that Anthem’s acquisition of Cigna would violate federal antitrust laws, the court has protected consumers and the competition on which they rely. I thank the hardworking staff of the Antitrust Division and our state partners, who conducted a thorough investigation and offered a clear and compelling presentation across a two-phase trial and never wavered in their commitment to protect competition in these markets.”

Today’s decision follows a trial that ran from Nov. 21, 2016, to Jan. 3, 2017. In July 2016, the Justice Department along with 11 states and the District of Columbia sued to stop the merger. The complaint alleged that a combined Anthem and Cigna would substantially lessen competition in the health insurance industry in dozens of markets across the country.

The district court’s opinion is temporarily under seal to allow the parties to review for confidentiality.

The United States was joined in the lawsuit by the District of Columbia and the States of California, Colorado, Connecticut, Georgia, Iowa, Maine, Maryland, New Hampshire, New York, Tennessee and Virginia.