Medicare Advantage in Marion County, Illinois
3,243 people in Marion County, Illinois were enrolled in Medicare Advantage in October 2026, 33.0% of 9,817 eligible beneficiaries (+1.7 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 48% of reported enrollment; 5 parent organizations have 11 or more members and the HHI is 3,904 (highly concentrated). HRSA classifies the county as fully rural. For 2027, 218 members here are in plans that terminate or leave the county. MA plans offered go from 20 to 13.
Parent organizations in Marion County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 1,529 | +167 | 48.0% |
| CVS Health Corporation | 1,246 | +114 | 39.1% |
| Humana Inc. | 242 | +11 | 7.6% |
| Centene Corporation | 114 | −18 | 3.6% |
| Molina Healthcare, Inc. | 56 | −24 | 1.8% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 2,311 beneficiaries in Marion County were assigned to 42 Medicare Shared Savings Program ACOs, 40.6% of assignable Original Medicare beneficiaries. Together, roughly 60% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.