Page 1 GAO-25-107194 Health Insurance Market Concentration
November 14, 2024
Congressional Committees
Private Health Insurance: Market Concentration Generally Increased from 2011 through
2022
Private health insurance is the most common source of health insurance coverage in the United
States—covering approximately two-thirds of the United States population in 2022, according to
the United States Census Bureau. The market for private health insurance in the United States
historically has been concentrated, meaning a small number of issuers of insurance plans
enrolled most of the people in a given market.
1
In our 2022 report on health insurance market
concentration, we considered a market concentrated in a state if three or fewer issuers held at
least 80 percent of the market share of enrollment among consumers.
2
We found that each of the three types of health insurance markets were concentrated from 2011
through 2020—the large-group market (coverage offered by large employers), the small-group
market (coverage offered by small employers), and the individual market (coverage primarily
sold directly to individual consumers who lack access to group coverage).
3
Within the individual
market, we reported a similar pattern in concentration starting in 2015 for those issuers
participating in the individual insurance exchanges—marketplaces operated by either the state
or federal government that were required to be established in each state by the Patient
Protection and Affordable Care Act (PPACA).
4
Highly concentrated insurance markets may
1
We use the term “issuer” when referring to the entities that are licensed by a state to engage in the business of
health insurance in that specific state.
2
See GAO, Private Health Insurance: Markets Remained Concentrated through 2020, with Increases in the Individual
and Small Group Markets, GAO-23-105672 (Washington D.C.: November 7, 2022).
3
Federal law defines a small employer as having an average of 1 to 50 employees during the preceding calendar
year; however, states may apply this definition based on an average of 1 to 100 employees. See 42 U.S.C. §§ 300gg-
91(e)(4),(7), 18024(b)(2)-(3).
4
Pub. L. No. 111-148, § 1321, 124 Stat. 119, 186 (2010). Health insurance exchanges are markets that operate
within each state’s overall individual and small-group market where eligible individuals and small employers can
compare and select among qualified insurance plans offered by participating issuers. In this report, the term “state”
includes the District of Columbia. States may choose to operate their own exchanges, or this responsibility can be
carried out by the federal government. In this report, we refer to exchanges in the individual health insurance market
as individual exchanges.
