The American Medical Association (AMA) released its latest look at concentration in health insurance, with UnitedHealth, Elevance Health and Aetna leading the way in market share.
UnitedHealth Group held the largest individual share of the commercial market in 2024 at 16%, followed by Elevance and Aetna, which both controlled about 12% of the market. Health Care Service Corp. was the only Blues plan to crack the top five with a 6% market share, but, if Blue Cross Blue Shield insurers were taken collectively, they controlled 43% of the commercial market.
Cigna rounded out the top five with a 9% market share, according to the report.
UnitedHealth also topped the list in Medicare Advantage (MA), with a 30% market share. The remaining top five insurers in that space were Humana (19%), Aetna (12%), Kaiser Permanente (6%) and Elevance Health (5%).
The study found that concentration in local commercial insurance markets has increased over the past decade. Based on federal guidelines, 97% of metro commercial insurance markets were concentrated in 2024 compared to 95% in 2014.
Concentration has declined, however, in MA, according to the report. Similar to the commercial space, 97% of MA markets were concentrated in 2024, down from 99% in 2017.
“In the vast majority of metropolitan areas across the country, health insurers hold outsized market share—leaving patients with fewer choices and higher costs,” said AMA CEO and Executive Vice President John J. Whyte, M.D., in a press release. “When one or two companies call the shots, premiums rise, options shrink, and patients suffer. Strengthening competition—not consolidation—is the path to lower costs and improved access.”
For the commercial market, 91% of metro areas saw one insurer control market share of at least 30%. In nearly half (47%) of regions, a single payer controlled at least 50% of the market share. BCBS plans held the largest market share across 84% of metro areas, per the study.
The five states with the lowest competition in the commercial space were Alabama, Kentucky, Hawaii, Michigan and Louisiana.
In MA, a single insurer held a 30% or more market share in 90% of regions, and, in 24% of metro areas, a single payer held market share of at least 50%.
UnitedHealth controlled the largest market share in 44% of metro areas for MA, with Humana having the largest share in 23% of regions. The five states with the least competitive markets in MA were Wyoming, the District of Columbia, Rhode Island, Montana and Nebraska.