Concentration in Health Insurance Markets

This interactive chart provides details on 1) enrollment in the overall individual market and the individual exchanges as measured by covered life-years, and 2) covered life-years in each state's individual exchange as a proportion of covered life-years in the overall individual market from 2015 through 2022.



Maine

Source: GAO analysis of data from the Centers for Medicare & Medicaid Services (CMS). | GAO-25-107194


The table below displays data for the selected state. Click here to download the data used in this graphic.



State Year Covered life-years, individual exchange Covered life-years, individual market Individual exchange covered life-years as a proportion of overall individual market (%)
Maine 2015 63,731 81,091 79
Maine 2016 71,504 87,765 81
Maine 2017 65,984 78,872 84
Maine 2018 64,107 72,763 88
Maine 2019 59,193 67,145 88
Maine 2020 55,084 62,585 88
Maine 2021 55,961 64,302 87
Maine 2022 60,059 67,847 89

  • We calculated the size of each market from 2015 through 2022 using covered life-years that issuers reported to Centers for Medicare & Medicaid Services or states. This measure is calculated as the average number of lives insured each month in the reporting year. Rather than a point-in-time measurement, this measure accounts for changes in enrollment that occur throughout the year.
  • Covered life-years is one of several ways to measure health insurance enrollment, so it may differ from other measures of market size.
  • We rounded market share values of less than 0.5 percent to zero.