AMA report: Health insurance giants tighten grip on U.S. markets

The American Medical Association (AMA) released new data showing which health insurers hold the largest share of the commercial and Medicare Advantage markets—spots where limited competition leaves millions of Americans with too few choices and rising costs.

The newest edition of Competition in Health Insurance: A Comprehensive Study of U.S. Markets (PDF) analyzes 2024 data across 384 metropolitan areas, all 50 states, and the District of Columbia. The report identifies the two largest insurers in each market and measures how concentrated those markets have become using federal merger guidelines issued in December 2023. Markets that cross thresholds set by the guidelines are considered “highly concentrated”—meaning consumers may not be getting the benefit of real competition.

“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, MD, MPH. “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.”

Highlights from the AMA’s latest study of competition in health insurance markets show:

Commercial markets

• Nationally, the 10 largest health insurers by market share were: 1. UnitedHealth Group (16%), 2. Elevance Health (12%), 3. CVS (Aetna) (12%), 4. Cigna (9%), 5. Health Care Service Corp. (8%), 6. Kaiser Permanente (6%), 7. Centene (3%), 8. Blue Cross Blue Shield of Florida (2%), 9. Blue Cross Blue Shield of Michigan (2%), 10. Highmark (2%). Collectively, however, Blue Cross Blue Shield insurers would lead the list with a combined commercial market share of 43%.
• A lack of competition has spread in the last decade as more local markets have become highly concentrated. Under federal guidelines, 97% (372) of metro area markets were highly concentrated in 2024 — up from 95% in 2014.
• In 91% (350) of metro areas, at least one insurer held a commercial market share of 30% or greater, and in 47% (179) of metro areas, one health insurer held a market share of at least 50%.
• Blue Cross Blue Shield insurers had the largest market shares in 84% (321) of metro areas, giving them the widest reach. Among individual insurers, Elevance Health had the largest footprint as the largest insurer in 21% (82) of metro areas.
• The 10 states (PDF) with the least competitive commercial health insurance markets were: 1. Alabama, 2. Kentucky, 3. Hawaii, 4. Michigan, 5. Louisiana, 6. Illinois, 7. Alaska, 8. Vermont, 9. Delaware, and 10. West Virginia.

Medicare Advantage markets

• Nationally, the 10 largest health insurers by market share were: 1. UnitedHealth Group {30%), 2. Humana (19%), 3. CVS (Aetna) (12%), 4. Kaiser Permanente (6%), 5, Elevance Health (5%), 6. Centene (4%), 7. Cigna (2%), 8. Blue Cross Blue Shield of Michigan (2%), 9. Highmark (1%), 10. SCAN (1%).
• Competition slightly improved in the last seven years as fewer local markets were highly concentrated, though the vast majority of markets remain highly concentrated. Under federal guidelines, 97% (372) of metro area markets were highly concentrated in 2024 - down from 99% in 2017.
• In 90% (345) of metro areas, at least one insurer held a market share of 30% or greater and in 24% (92) of metro areas, one insurer’s share was at least 50%.
• UnitedHealth Group had the largest market share in 44% (169) of metro areas, giving them the widest reach, followed by Humana, which had the largest market share in 23% (87) of metro areas.
• The 10 states (PDF) with the least competitive Medicare Advantage markets were: 1. Wyoming, 2. District of Columbia, 3. Rhode Island, 4. Montana, 5. Nebraska, 6. Utah, 7. West Virginia, 8. Mississippi, 9. Oklahoma, 10. Louisiana.

The prospect of future consolidation in the health insurance industry must be viewed in the context of the low levels of competition in most health insurance markets. For more than 20 years, the AMA analysis has been a helpful resource to researchers, policymakers, and regulators as they work to identify markets where mergers and acquisitions involving health insurers may cause competitive harm to consumers and providers of care.

Competition in Health Insurance: A Comprehensive Study of U.S. Markets is a vital element of AMA’s continued antitrust advocacy to protect patients and physicians from anticompetitive harm and help regulators and lawmakers better scrutinize anticompetitive insurer behavior. Health insurance market concentration will continue to be a vital issue of public policy for the AMA and the nation’s patients and physicians. Additional content from the updated study is available for download from the AMA’s Competition in Health Care Research website.

 About the American Medical Association

The American Medical Association is the physicians’ powerful ally in patient care. As the only medical association that convenes 190+ state and specialty medical societies and other critical stakeholders, the AMA represents physicians with a unified voice to all key players in health care.  The AMA leverages its strength by removing the obstacles that interfere with patient care, leading the charge to prevent chronic disease and confront public health crises and, driving the future of medicine to tackle the biggest challenges in health care.