Concentration in Health Insurance Markets
About two-thirds of Americans received health insurance through private plans in 2022. People may enroll in these private insurance plans through various markets, including:
- The individual health insurance market, which offers coverage directly to individuals. The individual exchanges, a subset of the overall individual market, are marketplaces in each state operated by the state or federal government. You can also view overall individual market and individual exchange enrollment data by state..
- The small-group health insurance market, which offers coverage through small employers.
- The large-group health insurance market, which offers coverage through large employers.
In this report, we find that private health insurance markets overall were concentrated from 2011 through 2022; most people who enrolled in a private health insurance plan did so with one of a small number of insurance companies. However, the markets for individuals became slightly less concentrated from 2020 through 2022. This concentration in the health insurance market can lead to increases in insurance premiums, which can reduce patients' access to affordable health insurance.
This interactive map provides information on health insurance markets by year and market type. Select a market type (e.g., Small-Group Market) and year (e.g., 2011) to see country-wide data and the associated data table. You can also hover over a state to see more detailed information. Clicking on the play button or moving the slider under the map will show you how the data changes over time for a market type. You can also download the data used in this graphic.
Individual Market
Legend
Largest three issuers hold less than 80% market share
Largest three issuers hold 80-100% market share. Darker blue indicates that this number is closer to 100%.
Source: GAO analysis of data from the Centers for Medicare & Medicaid Services (CMS). | GAO-25-107194
The table below displays data for the selected market and year. Click here to download the data used in this graphic.
| State | Year | No. of Issuers | Largest Issuer | Largest Issuer Market Share (%) | Second Largest Issuer | Second Largest Issuer Market Share (%) | Third Largest Issuer | Third Largest Issuer Market Share (%) | Combined Market Share of 3 Largest Issuers (%) | Change in 3 Largest Issuer Market Share, 2011-2022 (%) |
|---|---|---|---|---|---|---|---|---|---|---|
| Alabama | 2017 | 10 | BCBS OF ALABAMA GRP | 98 | UNITEDHEALTH GRP | 2 | AMERICAN INTL GRP | 0 | 100 | 3 |
| Alaska | 2017 | 5 | PREMERA BLUE CROSS GRP | 99 | AMERICAN INTL GRP | 1 | AETNA GRP | 0 | 100 | 31 |
| Arizona | 2017 | 15 | CENTENE CORP GRP | 44 | BCBS OF ARIZONA INC | 40 | UNITEDHEALTH GRP | 12 | 96 | -1 |
| Arkansas | 2017 | 13 | ARKANSAS BCBS GRP | 64 | CENTENE CORP GRP | 24 | CATHOLIC HLTH INITIATIVES GRP | 11 | 99 | 9 |
| California | 2017 | 27 | BLUE SHIELD OF CALIFORNIA GRP | 30 | KAISER FOUNDATION GRP | 28 | WELLPOINT INC GRP | 24 | 81 | 1 |
| Colorado | 2017 | 17 | KAISER FOUNDATION GRP | 41 | WELLPOINT INC GRP | 27 | CIGNA HEALTH GRP | 19 | 88 | 30 |
| Connecticut | 2017 | 9 | HIP INS GRP | 61 | WELLPOINT INC GRP | 35 | UNITEDHEALTH GRP | 2 | 98 | 18 |
| Delaware | 2017 | 8 | HIGHMARK GRP | 73 | AETNA GRP | 26 | UNITEDHEALTH GRP | 1 | 100 | 18 |
| District of Columbia | 2017 | 8 | CAREFIRST INC GRP | 85 | KAISER FOUNDATION GRP | 14 | AMERICAN INTL GRP | 1 | 99 | 14 |
| Florida | 2017 | 20 | BCBS OF FLORIDA INC | 60 | MOLINA HEALTHCARE INC GRP | 17 | CENTENE CORP GRP | 12 | 89 | 12 |
| Georgia | 2017 | 17 | WELLPOINT INC GRP | 56 | CENTENE CORP GRP | 26 | KAISER FOUNDATION GRP | 10 | 91 | 4 |
| Hawaii | 2017 | 6 | HAWAII MEDICAL SERVS ASSOC | 59 | KAISER FOUNDATION GRP | 40 | AMERICAN INTL GRP | 1 | 100 | 1 |
| Idaho | 2017 | 11 | BLUE CROSS OF IDAHO HEALTH SERVS INC | 35 | IHC INC GRP | 29 | BRIDGESPAN HEALTH CO | 15 | 79 | -4 |
| Illinois | 2017 | 18 | HCSC GRP | 73 | CARLE HOLDING CO GRP | 9 | CENTENE CORP GRP | 7 | 90 | 10 |
| Indiana | 2017 | 14 | WELLPOINT INC GRP | 28 | CENTENE CORP GRP | 26 | CARESOURCE MANAGEMENT GRP | 18 | 73 | 16 |
| Iowa | 2017 | 12 | WELLMARK INC GRP | 63 | AETNA GRP | 23 | MEDICA GRP | 9 | 96 | 7 |
| Kansas | 2017 | 15 | BCBS OF KANSAS GRP | 61 | BCBS OF KC GRP | 31 | MEDICA GRP | 5 | 97 | 20 |
| Kentucky | 2017 | 15 | WELLPOINT INC GRP | 78 | CARESOURCE MANAGEMENT GRP | 20 | HUMANA GRP | 1 | 99 | 3 |
| Louisiana | 2017 | 15 | LOUISIANA HEALTH SERVS GRP | 76 | HUMANA GRP | 14 | VANTAGE HEALTH PLAN INC | 8 | 98 | 14 |
| Maine | 2017 | 8 | MAINE COMM HEALTH OPTIONS | 40 | WELLPOINT INC GRP | 34 | HARVARD PILGRIM HTH CARE GRP | 24 | 99 | 8 |
| Maryland | 2017 | 13 | CAREFIRST INC GRP | 77 | KAISER FOUNDATION GRP | 21 | UNITEDHEALTH GRP | 2 | 99 | 13 |
| Massachusetts | 2017 | 20 | TUFTS HEALTH PLAN | 41 | BOSTON MEDICAL CENTER HEALTH PLAN INC | 22 | BCBS OF MA GRP | 14 | 77 | -6 |
| Michigan | 2017 | 18 | BCBS OF MICHIGAN GRP | 49 | SPECTRUM HEALTH GRP | 26 | HENRY FORD HEALTH SYSTEMS GRP | 6 | 81 | 14 |
| Minnesota | 2017 | 15 | HEALTHPARTNERS GRP | 38 | BCBS OF MN GRP | 26 | MEDICA HEALTH PLANS OF WISCONSIN | 19 | 83 | -3 |
| Mississippi | 2017 | 14 | CENTENE CORP GRP | 45 | MISSISSIPPI INS GRP | 44 | UNITEDHEALTH GRP | 6 | 95 | 9 |
| Missouri | 2017 | 18 | WELLPOINT INC GRP | 45 | CIGNA HEALTH GRP | 24 | BCBS OF KC GRP | 14 | 82 | 14 |
| Montana | 2017 | 11 | HCSC GRP | 51 | MONTANA HEALTH COOP | 30 | PACIFICSOURCE HEALTH PLAN GRP | 19 | 100 | 17 |
| Nebraska | 2017 | 13 | AETNA GRP | 36 | BCBS OF NEBRASKA | 31 | MEDICA GRP | 28 | 94 | 7 |
| Nevada | 2017 | 11 | UNITEDHEALTH GRP | 58 | WELLPOINT INC GRP | 32 | SAINT MARYS HEALTH CARE CORP GRP | 4 | 94 | -6 |
| New Hampshire | 2017 | 8 | WELLPOINT INC GRP | 37 | HARVARD PILGRIM HTH CARE GRP | 26 | MINUTEMAN HLTH INC | 20 | 82 | 7 |
| New Jersey | 2017 | 14 | BCBS OF NJ GRP | 72 | INDEPENDENCE HEALTH GRP INC | 26 | AMERICAN INTL GRP | 1 | 99 | 8 |
| New Mexico | 2017 | 13 | MOLINA HEALTHCARE INC GRP | 40 | NEW MEXICO HEALTH CONNECTIONS | 27 | PRESBYTERIAN HEALTHCARE SERVS GRP | 21 | 89 | -15 |
| New York | 2017 | 28 | NEW YORK STATE CATHOLIC HEALTH PLAN INC | 17 | AMERICAN INTL GRP | 15 | WELLPOINT INC GRP | 13 | 45 | -1 |
| North Carolina | 2017 | 14 | BCBS OF NORTH CAROLINA | 96 | CIGNA HEALTH GRP | 3 | UNITEDHEALTH GRP | 1 | 99 | -2 |
| North Dakota | 2017 | 7 | NORIDIAN MUTUAL INS CO | 82 | SANFORD HEALTH PLAN/SANFORD HEALTH PLAN OF MINNESOTA | 9 | MEDICA GRP | 8 | 100 | 11 |
| Ohio | 2017 | 20 | MEDICAL MUTUAL OF OHIO | 31 | WELLPOINT INC GRP | 28 | CARESOURCE MANAGEMENT GRP | 18 | 78 | -30 |
| Oklahoma | 2017 | 15 | HCSC GRP | 94 | UNITEDHEALTH GRP | 4 | COMMUNITYCARE GRP | 2 | 100 | 8 |
| Oregon | 2017 | 17 | PROVIDENCE HEALTH PLAN | 46 | KAISER FOUNDATION GRP | 21 | OREGON DENTAL GRP | 10 | 77 | 10 |
| Pennsylvania | 2017 | 22 | INDEPENDENCE HEALTH GRP INC | 38 | UPMC HEALTH OPTIONS INC | 27 | HIGHMARK GRP | 14 | 78 | 8 |
| Rhode Island | 2017 | 7 | BCBS OF RHODE ISLAND | 61 | NEIGHBORHOOD HLTH PLAN OF RI INC | 38 | AMERICAN INTL GRP | 0 | 100 | 0 |
| South Carolina | 2017 | 13 | BCBS OF SC GRP | 96 | UNITEDHEALTH GRP | 4 | AMERICAN INTL GRP | 0 | 100 | 18 |
| South Dakota | 2017 | 9 | AVERA HEALTH PLANS INC | 41 | WELLMARK GRP | 39 | SANFORD HEALTH PLAN/SANFORD HEALTH PLAN OF MINNESOTA | 18 | 98 | 12 |
| Tennessee | 2017 | 14 | BCBS OF TN INC | 27 | TRH HEALTH INS CO | 25 | HUMANA GRP | 23 | 74 | -15 |
| Texas | 2017 | 31 | HCSC GRP | 40 | MOLINA HEALTHCARE INC GRP | 18 | CENTENE CORP GRP | 15 | 73 | -19 |
| Utah | 2017 | 13 | IHC INC GRP | 60 | MOLINA HEALTHCARE INC GRP | 31 | REGENCE GRP | 6 | 97 | 8 |
| Vermont | 2017 | 5 | BCBS OF VT GRP | 80 | MVP GRP | 20 | AMERICAN INTL GRP | 0 | 100 | 1 |
| Virginia | 2017 | 20 | WELLPOINT INC GRP | 50 | INNOVATION HEALTH INS CO | 14 | KAISER FOUNDATION GRP | 11 | 76 | -9 |
| Washington | 2017 | 16 | KAISER FOUNDATION GRP | 30 | REGENCE GRP | 21 | PREMERA BLUE CROSS GRP | 20 | 71 | -25 |
| West Virginia | 2017 | 12 | HIGHMARK GRP | 78 | CARESOURCE WEST VIRGINIA CO | 15 | UNITEDHEALTH GRP | 5 | 98 | 28 |
| Wisconsin | 2017 | 24 | MOLINA HEALTHCARE INC GRP | 21 | DEAN HEALTH GRP | 14 | DEAN HEALTH GROUP | 11 | 46 | -3 |
| Wyoming | 2017 | 9 | BCBS OF WYOMING | 96 | UNITEDHEALTH GRP | 3 | AMERICAN NATL FIN GRP | 0 | 100 | 40 |
- Our analysis includes the 50 states and the District of Columbia.
- 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.
- Small and large employers may offer fully insured group plans (by purchasing coverage from an issuer) or self-funded group plans (by setting aside funds to pay for employee health care). Most small employers purchase fully insured plans, while most large employers self-fund at least some of their employee health benefits. For the small-group and large-group markets, enrollment data are from fully insured plans only.
- Where multiple issuers in a state shared a parent company, we aggregated the individual issuers to the parent company level. We calculated issuers' market share using covered life-years that issuers reported to Centers for Medicare & Medicaid Services, which measure the average number of lives insured, including dependents, on a pre-specified day of each month of the 12 months in the reporting year. Rather than a point-in-time measurement, this measure accounts for changes in enrollment that occur throughout the year. Market share refers to the ratio of the enrollment for each issuer in a state to the total enrollment in that state.
- Covered life-years is one of several ways to measure health insurance enrollment, so it may differ from other measures of market size.
- Names for some issuers have changed over time. For the purposes of this graphic, we have presented the issuer name associated with a given year.
- We rounded market share values of less than 0.5 percent to zero.