WASHINGTON — A federal appeals court on Friday left in place a decision blocking Blue Cross-Blue Shield insurer Anthem’s bid to buy rival Cigna, saying that a bigger company is not better for consumers.

The 2-1 decision upholds a federal judge’s ruling in February that said the proposed $48 billion acquisition would further reduce competition in the already concentrated health insurance market.

Anthem argued the combination would save $2.4 billion in medical costs and lead to lower consumer premiums. But the Justice Department said Anthem had no real plan to reach those savings. The government sued last summer to block the deal amid concerns over its effect on prices and consumer choices. The case went to trial late last year.

The ruling from the U.S. Court of Appeals for the District of Columbia Circuit likely dooms an acquisition bid that has lasted nearly two years. Even Cigna has soured on the deal, filing a separate lawsuit seeking a $1.85 billion termination fee from Anthem and billions more in damages.

Consumer groups also had opposed the deal, arguing it would leave consumers fewer choices. Industry experts suggested any consumer impact from the deal would take years to materialize and could lead to savings in some areas but higher costs elsewhere.

Writing for the majority, Judge Judith Rogers said the lower court was correct to halt the acquisition “based on Anthem’s failure to show the kind of extraordinary efficiencies necessary to offset the conceded anticompetitive effect” of the deal.

In dissent, Judge Brett Kavanaugh said a merger would allow the resulting larger company to negotiate lower provider rates and mean cost-savings for consumers.

He said he would send the case back to the lower court for further deliberations.

Anthem had pushed the deal as a way to help the companies negotiate better prices with pharmaceutical companies, hospitals and doctor groups. The company also said the deal would help cut expenses and add more customers, which helps insurers spread out the cost of investing in technology to manage and improve care.

CEO Joseph Swedish also has said the Cigna deal would help it stabilize pricing in the volatile public exchanges created by the Affordable Care Act. The Indianapolis-based insurer, which sells coverage in big states like California and New York, is a significant player in that market.

It offers plans on exchanges in 14 states and covers more than 1 million people.

Swedish said earlier this week that Anthem is making tentative plans to return to the exchanges next year, but that could change if it doesn’t know for certain by early June whether the government will fund an important cost-sharing subsidy for consumers.

Anthem Inc. announced its bid for Bloomfield, Connecticut-based Cigna Corp. during a wave of acquisitions that swept through the managed care sector in the summer of 2015. Of the three deals announced then, only Medicaid specialist Centene Corp.’s approximately $6.3 billion bid for Health Net has closed.

Earlier this year, another federal judge blocked Aetna Inc.’s roughly $34 billion acquisition of Medicare Advantage coverage provider Humana Inc. Aetna then said it was abandoning its deal.

Anthem representatives did not immediately respond on Friday to a request for comment about its next steps.

Friday’s decision generated little surprise on Wall Street, where Anthem shares slipped a little deeper than the broader market, and Cigna’s stock was little changed.