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 | 2021 | 7 | BCBS OF ALABAMA GRP | 98 | BRIGHT HEALTH GRP | 1 | UNITEDHEALTH GRP | 1 | 100 | 3 |
| Alaska | 2021 | 5 | PREMERA BLUE CROSS GRP | 92 | MODA ASSURANCE CO | 7 | AMERICAN INTL GRP | 0 | 100 | 31 |
| Arizona | 2021 | 11 | CENTENE CORP GRP | 38 | BCBS OF ARIZONA INC | 36 | OSCAR HEALTH INC GRP | 10 | 84 | -1 |
| Arkansas | 2021 | 7 | ARKANSAS BCBS GRP | 56 | CENTENE CORP GRP | 43 | UNITEDHEALTH GRP | 1 | 100 | 9 |
| California | 2021 | 19 | KAISER FOUNDATION GRP | 35 | BLUE SHIELD OF CALIFORNIA GRP | 34 | CENTENE CORP GRP | 9 | 78 | 1 |
| Colorado | 2021 | 14 | WELLPOINT INC GRP | 31 | KAISER FOUNDATION GRP | 23 | BRIGHT HEALTH GRP | 21 | 75 | 30 |
| Connecticut | 2021 | 7 | HIP INS GRP | 73 | WELLPOINT INC GRP | 26 | AMERICAN INTL GRP | 1 | 100 | 18 |
| Delaware | 2021 | 6 | HIGHMARK GRP | 100 | AMERICAN INTL GRP | 0 | UNITEDHEALTH GRP | 0 | 100 | 18 |
| District of Columbia | 2021 | 5 | CAREFIRST INC GRP | 83 | KAISER FOUNDATION GRP | 16 | AMERICAN INTL GRP | 1 | 100 | 14 |
| Florida | 2021 | 15 | BCBS OF FLORIDA INC | 53 | CENTENE CORP GRP | 15 | BRIGHT HEALTH GRP | 12 | 81 | 12 |
| Georgia | 2021 | 14 | CENTENE CORP GRP | 61 | WELLPOINT INC GRP | 17 | KAISER FOUNDATION GRP | 8 | 86 | 4 |
| Hawaii | 2021 | 4 | HAWAII MEDICAL SERVS ASSOC | 66 | KAISER FOUNDATION GRP | 33 | AMERICAN INTL GRP | 1 | 100 | 1 |
| Idaho | 2021 | 7 | BLUE CROSS OF IDAHO HEALTH SERVS INC | 41 | IHC INC GRP | 34 | REGENCE GRP | 14 | 89 | -4 |
| Illinois | 2021 | 16 | HCSC GRP | 70 | CENTENE CORP GRP | 12 | CARLE HOLDING CO GRP | 8 | 91 | 10 |
| Indiana | 2021 | 7 | CARESOURCE MANAGEMENT GRP | 54 | CENTENE CORP GRP | 39 | UNITEDHEALTH GRP | 5 | 98 | 16 |
| Iowa | 2021 | 8 | WELLMARK GRP | 77 | MEDICA GRP | 19 | UNITEDHEALTH GRP | 2 | 99 | 7 |
| Kansas | 2021 | 11 | BCBS OF KANSAS GRP | 49 | SUNFLOWER STATE HEALTH PLAN INC | 33 | BCBS OF KC GRP | 8 | 90 | 20 |
| Kentucky | 2021 | 12 | WELLPOINT INC GRP | 52 | CARESOURCE MANAGEMENT GRP | 48 | AMERICAN INTL GRP | 0 | 100 | 3 |
| Louisiana | 2021 | 10 | LOUISIANA HEALTH SERVS GRP | 97 | CHRISTUS HEALTH PLAN LOUISIANA | 2 | UNITEDHEALTH GRP | 1 | 100 | 14 |
| Maine | 2021 | 6 | WELLPOINT INC GRP | 41 | HARVARD PILGRIM HTH CARE GRP | 39 | MAINE COMM HEALTH OPTIONS | 20 | 100 | 8 |
| Maryland | 2021 | 9 | CAREFIRST INC GRP | 73 | KAISER FOUNDATION GRP | 25 | UNITEDHEALTH GRP | 2 | 100 | 13 |
| Massachusetts | 2021 | 14 | TUFTS HEALTH PLAN | 50 | BOSTON MEDICAL CENTER HEALTH PLAN INC | 23 | BCBS OF MA GRP | 12 | 84 | -6 |
| Michigan | 2021 | 11 | BCBS OF MICHIGAN GRP | 48 | SPECTRUM HEALTH GRP | 37 | MOLINA HEALTHCARE INC GRP | 4 | 89 | 14 |
| Minnesota | 2021 | 14 | UCARE MINNESOTA | 37 | BCBS OF MN GRP | 24 | MEDICA GRP | 19 | 80 | -3 |
| Mississippi | 2021 | 9 | CENTENE CORP GRP | 53 | MISSISSIPPI INS GRP | 24 | MOLINA HEALTHCARE INC GRP | 20 | 97 | 9 |
| Missouri | 2021 | 15 | CENTENE CORP GRP | 40 | CIGNA HEALTH GRP | 21 | WELLPOINT INC GRP | 17 | 78 | 14 |
| Montana | 2021 | 6 | HCSC GRP | 40 | MONTANA HEALTH COOP | 36 | PACIFICSOURCE HEALTH PLAN GRP | 24 | 100 | 17 |
| Nebraska | 2021 | 8 | MEDICA GRP | 76 | BRIGHT HEALTH GRP | 20 | UNITEDHEALTH GRP | 3 | 100 | 7 |
| Nevada | 2021 | 9 | UNITEDHEALTH GRP | 59 | WELLPOINT INC GRP | 13 | FRIDAY HEALTH PLANS GRP | 10 | 82 | -6 |
| New Hampshire | 2021 | 5 | WELLPOINT INC GRP | 49 | CENTENE CORP GRP | 38 | HARVARD PILGRIM HTH CARE GRP | 13 | 100 | 7 |
| New Jersey | 2021 | 9 | BCBS OF NJ GRP | 62 | INDEPENDENCE BLUE CROSS GRP | 34 | OSCAR HEALTH INC GRP | 3 | 99 | 8 |
| New Mexico | 2021 | 10 | MOLINA HEALTHCARE INC GRP | 47 | TRUE HEALTH NEW MEXICO INC | 30 | HCSC GRP | 11 | 88 | -15 |
| New York | 2021 | 20 | NEW YORK STATE CATHOLIC HEALTH PLAN INC | 28 | AMERICAN INTL GRP | 16 | HEALTHFIRST PHSP INC | 10 | 54 | -1 |
| North Carolina | 2021 | 11 | BCBS OF NORTH CAROLINA | 76 | BRIGHT HEALTH GRP | 16 | CIGNA HEALTH GRP | 3 | 96 | -2 |
| North Dakota | 2021 | 6 | BCBS OF NORTH DAKOTA | 60 | SANFORD HEALTH PLAN/SANFORD HEALTH PLAN OF MINNESOTA | 37 | MEDICA GRP | 3 | 100 | 11 |
| Ohio | 2021 | 14 | MEDICAL MUTUAL OF OHIO | 25 | CENTENE CORP GRP | 25 | CARESOURCE MANAGEMENT GRP | 17 | 66 | -30 |
| Oklahoma | 2021 | 12 | HCSC GRP | 81 | MEDICA GRP | 9 | BRIGHT HEALTH GRP | 7 | 96 | 8 |
| Oregon | 2021 | 9 | PROVIDENCE HEALTH PLAN | 31 | KAISER FOUNDATION GRP | 24 | OREGON DENTAL GRP | 19 | 74 | 10 |
| Pennsylvania | 2021 | 17 | INDEPENDENCE BLUE CROSS GRP | 36 | UPMC HEALTH OPTIONS INC | 25 | HIGHMARK GRP | 17 | 78 | 8 |
| Rhode Island | 2021 | 5 | NEIGHBORHOOD HLTH PLAN OF RI INC | 60 | BCBS OF RHODE ISLAND | 40 | AMERICAN INTL GRP | 0 | 100 | 0 |
| South Carolina | 2021 | 10 | BCBS OF SC GRP | 82 | MOLINA HEALTHCARE INC GRP | 11 | ABSOLUTE TOTAL CARE INC | 4 | 97 | 18 |
| South Dakota | 2021 | 8 | AVERA HEALTH PLANS INC | 39 | SANFORD HEALTH PLAN/SANFORD HEALTH PLAN OF MINNESOTA | 34 | WELLMARK GRP | 26 | 99 | 12 |
| Tennessee | 2021 | 12 | CIGNA HEALTH GRP | 36 | BCBS OF TN INC | 31 | TRH HEALTH INS CO | 12 | 79 | -15 |
| Texas | 2021 | 20 | HCSC GRP | 35 | MOLINA HEALTHCARE INC GRP | 23 | CENTENE CORP GRP | 23 | 80 | -19 |
| Utah | 2021 | 9 | IHC INC GRP | 79 | MOLINA HEALTHCARE INC GRP | 9 | UNIVERSITY OF UTAH HEALTH INS PLANS | 5 | 93 | 8 |
| Vermont | 2021 | 3 | BCBS OF VT GRP | 51 | MVP GRP | 49 | AMERICAN INTL GRP | 0 | 100 | 1 |
| Virginia | 2021 | 16 | WELLPOINT INC GRP | 54 | CIGNA HEALTH GRP | 23 | KAISER FOUNDATION GRP | 10 | 87 | -9 |
| Washington | 2021 | 15 | KAISER FOUNDATION GRP | 31 | MOLINA HEALTHCARE INC GRP | 23 | PREMERA BLUE CROSS GRP | 22 | 76 | -25 |
| West Virginia | 2021 | 8 | HIGHMARK GRP | 60 | CARESOURCE MANAGEMENT GRP | 36 | UNITEDHEALTH GRP | 3 | 99 | 28 |
| Wisconsin | 2021 | 19 | COMMON GROUND HEALTHCARE COOP | 20 | MEDICA GRP | 13 | UNIVERSITY HEALTH CARE & GUNDERSEN LUTHERAN GRP | 11 | 43 | -3 |
| Wyoming | 2021 | 6 | BCBS OF WYOMING | 92 | MONTANA HEALTH COOP | 7 | UNITEDHEALTH GRP | 1 | 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.