CHICAGO –The American Medical Association (AMA) today published the newest annual edition of Competition in Health Insurance: A Comprehensive Study of U.S. Markets (PDF) with findings demonstrating the rise of highly concentrated markets for health insurance.

The updated study analyzed market concentration and health insurer market shares for 384 metropolitan statistical areas (MSAs), the 50 states and the District of Columbia. For the first time, the study also presents national-level market shares for the 10 largest health insurers in the U.S. The study’s findings show most health insurance markets in the U.S. are highly concentrated leaving millions of Americans with more limited health insurer options.

“As merger rumors involving health insurers swirl, the prospect of future consolidation in the health insurance industry should be more closely scrutinized given the low levels of competition in most health insurance markets,” said AMA President Gerald E. Harmon, M.D. “For two decades, the AMA study has been helping researchers, lawmakers, policymakers, and federal and state regulators identify markets where consolidation involving health insurers may cause competitive harm to consumers and providers of care.”

The AMA’s latest study of competition in commercial health insurance markets shows:

• Seventy-three percent (280) of MSA-level markets were high concentrated according to federal guidelines.
• Forty-six percent (178) of MSA-level markets had one insurer with a share of 50% or more.
• Between 2014 and 2020, the share of highly concentrated markets rose from 71% to 73%.
• Fifty-four percent of markets that were already highly concentrated in 2014 became even more concentrated by 2020.
• The health insurers with the highest market share in the most MSA-level markets were: 1. Anthem (80 MSAs), 2. Health Care Service Corp. (44 MSAs), 3. UnitedHealth Group and Blue Cross Blue Shield of Florida (each with 22 MSAs apiece), and 4. Highmark and Kaiser (each with 20 MSAs apiece).
• The 10 states (PDF) with the least competitive commercial health insurance markets were: 1. Alabama, 2. Michigan, 3. Louisiana, 4. South Carolina, 5. Hawaii, 6. Kentucky, 7. Alaska, 8. Illinois, 9. North Dakota, and 10. Oklahoma. See the 10 states with the least competitive PPO (PDF) or exchange (PDF) markets.
• Fourteen states (PDF) had one health insurer with a share of 50% or more of the commercial health insurance market.
• The 10 largest health insurers in the U.S. at the national-level by market share were: 1. UnitedHealth Group (15%), 2. Anthem (12%), 3. Aetna (11%), 4. Cigna (10%), 5. Kaiser (7%), 6. Health Care Service Corp. (6%), 7. Blue Cross Blue Shield of Michigan (2%), 8. Blue Cross Blue Shield of Florida (2%), 9. Blue Shield of California (2%), and 10. Centene (2%).

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 competitive harm. Health insurance market concentration will continue to be a vital issue of public policy for the AMA, the federation of medicine, and the nation’s physicians and patients. Content from the 2021 updated study is available for download from the AMA’s Competition in Health Insurance Research website.