CHICAGO – The American Medical Association (AMA) today identified the industry giants with the biggest shares of the markets for commercial health insurance, Medicare Advantage, and public health exchanges, where high levels of market concentration leaves millions of Americans with limited competitive options for health insurance.

The 2023 edition of Competition in Health Insurance: A Comprehensive Study of U.S. Markets (PDF) examined 381 metropolitan statistical areas (MSAs), the 50 states and the District of Columbia and tabulated market shares for the two largest health insurance companies. It also analyzed state and MSA-level market concentration according to measures used in current federal antitrust guidelines. Markets that exceed a regulatory threshold set by federal guidelines are considered “highly concentrated” and lack adequate health insurer competition.

“High market concentration tends to lower competition among health insurers, which can harm patients by raising insurance premiums above competitive levels,” said AMA President Jesse M. Ehrenfeld, M.D., M.P.H. “The share of markets that are highly concentrated may be far higher than reflected under current federal guidelines. The AMA supports draft federal guidelines that would lower the regulatory threshold for markets to be considered highly concentrated. To reverse the trend toward health insurance consolidation, the AMA strongly supports the proposal as the proper prescription to scrutinize and potentially limit harmful insurance mergers.”

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

Commercial markets

• Under current federal guidelines, 73% (277) of MSA-level markets were highly concentrated in 2022, up from 71% in 2014. Under proposed federal guidelines, 95% (363) of MSA-level markets would be highly concentrated.
• In 48% (184) of MSAs, one health insurer held a market share of at least 50%.
• Elevance Health (formerly Anthem) was the largest health insurer by market share in 22% (83) of MSAs, followed by Health Care Service Corp. with a market share lead in 11% (43) of MSAs and Highmark with a market share lead in 6% (22) of MSAs.
• At the national level, the 10 largest health insurers by market share were: 1. UnitedHealth Group (14%), 2. Elevance Health (12%), 3. CVS (Aetna) (11%), 4. Cigna (10%), 5. Kaiser Permanente (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. Highmark (2%). 

Medicare Advantage markets

• Under current federal guidelines, 71% (271) of MSA-level markets were highly concentrated in 2022, down from 87% in 2017. Under proposed federal guidelines, 97% (370) of MSA-level markets would be highly concentrated.
• In 31% (118) of MSAs, one health insurer held a market share of at least 50%.
• UnitedHealth Group was the largest health insurer by market share in 42% (161) of MSAs, followed by Humana with a market share lead in 22% (83) of MSAs, and CVS (Aetna) with a market share lead in 7% (25) of MSAs.
• At the national level, the 10 largest health insurers by market share were: 1. UnitedHealth Group (28%), 2. Humana (18%), 3. CVS (Aetna) 11%, 4. Kaiser Permanente (6%), 5. Elevance Health (6%), 6. Centene Corp. (5%), 7. Cigna (2%), 8. Blue Cross Blue Shield of Michigan (2%), 9. Highmark (1%), and 10. SCAN (1%).

Public health exchange markets

• Under current federal guidelines, 90% (339) of MSA-level markets were highly concentrated in 2022, down from 95% (307) in 2014. Under proposed federal guidelines, 99% (373) of MSA-level markets would be highly concentrated.
• In 67% (254) of MSAs, one health insurer held a market share of at least 50%.
• Centene Corp. was the largest health insurer by market share in 15% (56) of MSAs, followed by Elevance Health with a market share lead in 6% (23) of MSAs, and Blue Cross Blue Shield of Florida and Health Care Service Corp. each with a market share lead in 6% (21) of MSAs.
• At the national level, the 10 largest health insurers by market share were: 1. Centene Corp. (14%), 2. Blue Cross Blue Shield of Florida (9%), 3. Kaiser Permanente (7%), 4. Bright Health (7%), 5. Oscar Health (5%), 6. Elevance Health (4%), 7. Health Care Service Corp. (4%), 8. Blue Shield of California (4%), 9. Blue Cross Blue Shield of North Carolina (3%), and 10. Molina Healthcare (3%).

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, the federation of medicine, and the nation’s physicians and patients. Additional content from the updated study is available for download from the AMA’s Competition in Health Care Research website.

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Editor’s Note: For additional information, please see the new AMA viewpoint on the association’s support for greater federal scrutiny of health insurer mergers.