Concentration in Health Insurance Markets
About two-thirds of Americans received health insurance through private plans in 2024. 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 2024; 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 2024. 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) from the tabs and year (e.g., 2011) from the drop down 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.
Small-Group Market
Select a year to view its associated data table.
Source: GAO analysis of data from the Centers for Medicare & Medicaid Services (CMS). | GAO-27-108927
| 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, 2011-2024 (%) |
|---|---|---|---|---|---|---|---|---|---|---|
| Alabama | 2023 | 3 | BCBS OF ALABAMA GRP | 98 | VIVA HEALTH INC | 1 | UNITEDHEALTH GRP | 1 | 100 | 0 |
| Alaska | 2023 | 4 | PREMERA BLUE CROSS GRP | 92 | OREGON DENTAL GRP | 6 | UNITEDHEALTH GRP | 1 | 99 | 14 |
| Arizona | 2023 | 6 | BCBS OF ARIZONA INC | 42 | UNITEDHEALTH GRP | 40 | CVS HEALTH GRP | 9 | 92 | 43 |
| Arkansas | 2023 | 3 | ARKANSAS BCBS GRP | 70 | UNITEDHEALTH GRP | 15 | CENTENE CORP GRP | 15 | 100 | 5 |
| California | 2023 | 13 | KAISER FOUNDATION GRP | 36 | ELEVANCE HEALTH INC GRP | 23 | BLUE SHIELD OF CALIFORNIA GRP | 22 | 82 | 29 |
| Colorado | 2023 | 5 | UNITEDHEALTH GRP | 42 | ELEVANCE HEALTH INC GRP | 33 | KAISER FOUNDATION GRP | 24 | 99 | 23 |
| Connecticut | 2023 | 6 | ELEVANCE HEALTH INC GRP | 39 | UNITEDHEALTH GRP | 27 | CIGNA HEALTH GRP | 24 | 90 | 20 |
| Delaware | 2023 | 3 | HIGHMARK GRP | 91 | UNITEDHEALTH GRP | 8 | CVS HEALTH GRP | 1 | 100 | 5 |
| District of Columbia | 2023 | 5 | CAREFIRST INC GRP | 80 | UNITEDHEALTH GRP | 13 | KAISER FOUNDATION GRP | 5 | 98 | 3 |
| Florida | 2023 | 6 | BCBS OF FLORIDA INC | 60 | UNITEDHEALTH GRP | 35 | HUMANA GRP | 4 | 98 | 24 |
| Georgia | 2023 | 6 | UNITEDHEALTH GRP | 29 | HUMANA GRP | 26 | CIGNA HEALTH GRP | 22 | 77 | 15 |
| Hawaii | 2023 | 5 | HAWAII MEDICAL SERVS ASSOC | 51 | KAISER FOUNDATION GRP | 20 | UNIVERSITY HEALTH ALLIANCE | 19 | 91 | 11 |
| Idaho | 2023 | 9 | BLUE CROSS OF ID GRP | 36 | REGENCE GRP | 29 | IHC INC GRP | 21 | 85 | -9 |
| Illinois | 2023 | 9 | HCSC GRP | 86 | UNITEDHEALTH GRP | 11 | CARLE HOLDING CO GRP | 2 | 99 | 23 |
| Indiana | 2023 | 9 | ELEVANCE HEALTH INC GRP | 62 | UNITEDHEALTH GRP | 19 | PHP INDIANA GRP | 11 | 92 | 23 |
| Iowa | 2023 | 10 | WELLMARK GRP | 88 | UNITEDHEALTH GRP | 9 | MEDICAL ASSOCIATES CLINIC | 1 | 98 | 9 |
| Kansas | 2023 | 6 | BCBS OF KANSAS GRP | 80 | BCBS OF KC GRP | 7 | UNITEDHEALTH GRP | 6 | 93 | 20 |
| Kentucky | 2023 | 4 | ELEVANCE HEALTH INC GRP | 68 | HUMANA GRP | 21 | UNITEDHEALTH GRP | 11 | 100 | 7 |
| Louisiana | 2023 | 4 | LOUISIANA HEALTH SERVS GRP | 93 | UNITEDHEALTH GRP | 6 | HUMANA GRP | 1 | 100 | 5 |
| Maine | 2023 | 6 | HARVARD PILGRIM HTH CARE GRP | 41 | ELEVANCE HEALTH INC GRP | 34 | MAINE COMM HEALTH OPTIONS | 17 | 92 | -3 |
| Maryland | 2023 | 4 | CAREFIRST INC GRP | 78 | UNITEDHEALTH GRP | 14 | KAISER FOUNDATION GRP | 4 | 97 | 5 |
| Massachusetts | 2023 | 9 | BCBS OF MA GRP | 43 | HARVARD PILGRIM HTH CARE GRP | 25 | MASS GEN BRIGHAM HLTH PLAN GRP | 11 | 79 | -2 |
| Michigan | 2023 | 10 | BCBS OF MICHIGAN GRP | 61 | COREWELL HEALTH GRP | 24 | HENRY FORD HEALTH SYSTEMS GRP | 9 | 94 | 17 |
| Minnesota | 2023 | 7 | BCBS OF MN GRP | 60 | MEDICA GRP | 28 | UNITEDHEALTH GRP | 10 | 98 | 17 |
| Mississippi | 2023 | 3 | MISSISSIPPI INS GRP | 91 | UNITEDHEALTH GRP | 8 | HUMANA GRP | 1 | 100 | 3 |
| Missouri | 2023 | 8 | UNITEDHEALTH GRP | 43 | ELEVANCE HEALTH INC GRP | 37 | BCBS OF KC GRP | 14 | 94 | 24 |
| Montana | 2023 | 5 | HCSC GRP | 55 | PACIFICSOURCE HEALTH PLAN GRP | 34 | MONTANA HEALTH COOP | 9 | 98 | 9 |
| Nebraska | 2023 | 4 | BCBS OF NEBRASKA | 62 | UNITEDHEALTH GRP | 25 | MEDICA GRP | 12 | 99 | 13 |
| Nevada | 2023 | 6 | UNITEDHEALTH GRP | 69 | ELEVANCE HEALTH INC GRP | 22 | RENOWN HLTH GRP | 8 | 98 | 35 |
| New Hampshire | 2023 | 3 | ELEVANCE HEALTH INC GRP | 61 | HARVARD PILGRIM HTH CARE GRP | 31 | UNITEDHEALTH GRP | 8 | 100 | 1 |
| New Jersey | 2023 | 5 | BCBS OF NJ GRP | 71 | UNITEDHEALTH GRP | 21 | INDEPENDENCE BLUE CROSS GRP | 8 | 100 | 8 |
| New Mexico | 2023 | 3 | HCSC GRP | 54 | PRESBYTERIAN HEALTHCARE SERVS GRP | 23 | UNITEDHEALTH GRP | 23 | 100 | 14 |
| New York | 2023 | 11 | UNITEDHEALTH GRP | 47 | LIFETIME HEALTHCARE GRP | 18 | HIGHMARK GRP | 6 | 71 | 12 |
| North Carolina | 2023 | 4 | BCBS OF NC GRP | 71 | UNITEDHEALTH GRP | 27 | CVS HEALTH GRP | 2 | 99 | 5 |
| North Dakota | 2023 | 5 | BCBS OF NORTH DAKOTA | 81 | SANFORD HLTH GRP | 11 | MEDICA GRP | 7 | 99 | 0 |
| Ohio | 2023 | 9 | MEDICAL MUTUAL OF OHIO | 40 | ELEVANCE HEALTH INC GRP | 37 | UNITEDHEALTH GRP | 11 | 88 | 17 |
| Oklahoma | 2023 | 4 | HCSC GRP | 89 | COMMUNITYCARE GRP | 6 | UNITEDHEALTH GRP | 4 | 100 | 31 |
| Oregon | 2023 | 9 | REGENCE GRP | 36 | PROVIDENCE HLTH GRP | 30 | KAISER FOUNDATION GRP | 15 | 82 | 32 |
| Pennsylvania | 2023 | 8 | INDEPENDENCE BLUE CROSS GRP | 36 | UPMC HEALTH SYSTEM GRP | 28 | HIGHMARK GRP | 21 | 85 | 51 |
| Rhode Island | 2023 | 4 | BCBS OF RHODE ISLAND | 88 | UNITEDHEALTH GRP | 5 | NEIGHBORHOOD HLTH PLAN OF RI INC | 5 | 97 | -1 |
| South Carolina | 2023 | 3 | BCBS OF SC GRP | 88 | UNITEDHEALTH GRP | 12 | CVS HEALTH GRP | 0 | 100 | 11 |
| South Dakota | 2023 | 7 | WELLMARK GRP | 74 | AVERA HEALTH PLANS INC | 18 | SANFORD HLTH GRP | 7 | 99 | 9 |
| Tennessee | 2023 | 5 | BCBS OF TN INC | 66 | UNITEDHEALTH GRP | 30 | HUMANA GRP | 3 | 98 | 4 |
| Texas | 2023 | 7 | HCSC GRP | 86 | UNITEDHEALTH GRP | 8 | HUMANA GRP | 3 | 97 | 24 |
| Utah | 2023 | 6 | IHC INC GRP | 77 | REGENCE GRP | 18 | UNITEDHEALTH GRP | 4 | 100 | 28 |
| Vermont | 2023 | 2 | BLUE CARE NETWORK OF MICHIGAN | 58 | MVP GRP | 42 | -- | -- | 100 | 0 |
| Virginia | 2023 | 9 | ELEVANCE HEALTH INC GRP | 45 | UNITEDHEALTH GRP | 19 | CAREFIRST INC GRP | 19 | 84 | 8 |
| Washington | 2023 | 7 | REGENCE GRP | 46 | PREMERA BLUE CROSS GRP | 25 | KAISER FOUNDATION GRP | 22 | 92 | 18 |
| West Virginia | 2023 | 4 | HIGHMARK GRP | 91 | UNITEDHEALTH GRP | 6 | HEALTH PLAN GRP | 4 | 100 | 9 |
| Wisconsin | 2023 | 16 | UNITEDHEALTH GRP | 31 | ELEVANCE HEALTH INC GRP | 19 | UNIVERSITY HEALTH CARE & GUNDERSEN LUTHERAN GRP | 17 | 67 | 37 |
| Wyoming | 2023 | 4 | BCBS OF WYOMING | 78 | UNITEDHEALTH GRP | 12 | MONTANA HEALTH COOP | 10 | 100 | 14 |
- Our analysis includes the 50 states and the District of Columbia.
- Federal law defines a small employer as having an average of one to 50 employees during the preceding calendar year; however, states may apply this definition based on an average of one 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.