Most insurer markets are highly concentrated, including many regions where a single payer dominates at least half of the market share, according to a new analysis from the American Medical Association.
The AMA released an updated look at concentration in payer markets and found that across product lines, 73% of metropolitan statistical areas were highly concentrated in 2022. In most (90%) regions, a single payer owns a 30% market share, and in 48% of markets, one payer controls at least 50% of the share.
In 11% of markets, a single insurer has a 70% or higher market share, according to the report.
In an accompanying editorial, AMA President Jesse Ehrenfeld wrote that this level of concentration can have "profoundly negative effects on patients and physicians alike."
"Because insurers that control a dominant market share face a reduced level of competition, they have little or no incentive to reduce policyholder premiums," he wrote. "The opposite is true, however; monopolistic effects of mergers often produce higher premiums because consumers seeking coverage have fewer choices."
Market concentration is also growing, according to the analysis. In markets that were already highly concentrated by 2014, 14% became even more concentrated by 2022.
In addition, 29% of markets that were not highly concentrated in 2014 reached that category by 2022.
UnitedHealth Group is the largest national commercial player, and Centene is the largest insurer on the Affordable Care Act's exchanges, according to the report. A Blue Cross Blue Shield plan held the largest market share, however, in 82% of the MSAs in the study.
In the editorial, Ehrenfeld said that the AMA supports merger guidelines proposed earlier this year by the Federal Trade Commission and Department of Justice, as they would likely increase the scrutiny of insurance mergers and rein in future consolidation.
"In addition to supporting the draft merger guidelines, the AMA champions greater competition in those markets through antitrust advocacy, and also makes available to the federation of medicine model legislation that empowers physicians and checks anticompetitive mergers at the state level," Ehrenfeld wrote.