Most insurance markets are highly concentrated

Data: American Medical Association; Cartogram: Lazaro Gamio/Axios

A new study by the American Medical Association found that 73% of metropolitan areas have highly concentrated health insurance markets. One insurer had at least a 50% market share in almost half of the areas.

Between the lines: Insurers with a lot of market power can, in theory, raise premiums and pay providers less. But this study isn't proof that insurers in concentrated areas are doing that.

It does, however, cite other research finding that insurer consolidation has correlated with higher premiums.

  • Provider consolidation is another huge market trend to watch, and one study has found that insurers with more market power can drive lower prices in highly concentrated provider markets.