Private Health Insurance: Market Continues to Concentrate Through 2020, Increasing Individual and Small Group Markets

What GAO found

In November 2020, the GAO reported a spike in private health insurance plan enrollment from 2010 to 2018. Specifically, the GAO considered a state concentrated market if three or fewer issuers owned at least 80% of that market. GAO examines the individual (coverage sold directly to individuals), small group (coverage provided by small employers) and large group (coverage provided by large employers) markets. and found that this pattern continues in 2019 and 2020. In particular:

  • Each of the three 2020 markets was concentrated in at least 42 states (including the District of Columbia).
  • The individual and small group market has generally become more concentrated in recent years. The median market share of the top three issuers in each market increased by 12 percentage points and 10 percentage points respectively from 2011 to 2020. These increases resulted in a median market share of at least 97% in both markets in 2020.

Number of states with at least 80% subscribers in the top three issuers, including the District of Columbia, by market, 2011-2020

Number of states with at least 80% subscribers in the top three issuers, including the District of Columbia, by market, 2011-2020

GAO found similar high concentration patterns on individual market exchanges. A marketplace where consumers can compare and choose insurance plans offered by participating insurers, the exchange was established by the Patient Protection and Affordable Care Act (PPACA). From 2015 to 2020, most state exchanges were concentrated and have become more concentrated over time. This is often due to a decline in the number of issuers or an existing issuer increasing its market share within the state. In 2020, exchanges were concentrated in all states.

GAO received technical comments on drafts of this report from the Department of Health and Human Services and incorporated them where appropriate.

Why GAO did this study

Individuals have a variety of options for obtaining private health insurance, including through individual, small group, and large group markets. Concentration in the health insurance market may indicate reduced issuer competition, which may affect consumers’ choice of issuers and the premiums they pay for coverage.

The PPACA included provisions for the GAO to periodically review the concentration of the health insurance market. This report covers the overall individual, small group, and large group health insurance market and changes in enrollment concentration among issuers on individual market exchanges.

GAO determined market share in each of the three overall markets using 2019 and 2020 registration data that issuers are required to report to the Centers for Medicare & Medicaid Services (CMS). GAO used registration data from CMS to determine market share on individual market exchanges for 2018, 2019, and 2020. For all analyses, GAO used the most recent data available at the time of review.

For more information, please contact John Dicken ((202) 512-7114) or

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