Private Health Insurance: Market Concentration in 2024 Was Generally Higher Than in 2011

Multiple companies may sell health insurance in a given market, but only a small number of these insurers will have the most enrollees, as we previously reported. Known as market concentration, this can leave enrollees with fewer choices of insurers and higher premiums because of less competition in the market.

Market concentration generally increased from 2011 through 2024, with three or fewer insurers holding at least 80% market share for the individual and employer group markets in at least 36 states. However, concentration in the markets for individuals peaked in 2019 and has become slightly less concentrated since.

Map of the United States on a tablet, with some states colored in various shades of blue. It says HEALTH INSURANCE above the map.

Since 2014, GAO has reported that enrollment in private health insurance plans has been concentrated, meaning a small number of issuers, such as health insurers, enrolled most of the people in a given market. Specifically, GAO considers a market concentrated in a state if three or fewer issuers hold at least 80 percent of the market share of enrollment.

For this report, GAO examined the individual (coverage primarily sold to individuals who lack access to group coverage), small-group (coverage offered by small employers), and large-group (coverage offered by large employers) health insurance markets from 2011 through 2024 across states. GAO found that the number of states with concentrated markets generally increased, with recent decreases in the individual market (see figure).

Number of States, Including the District of Columbia, Where the Three Largest Issuers Had at Least 80 Percent of Enrollment, 2011 Through 2024

Note: The most recent years in GAO’s series on market concentration, 2023 and 2024, are highlighted in this figure.