Medicare Advantage in Madison County, Illinois
33,630 people in Madison County, Illinois were enrolled in Medicare Advantage in October 2026, 55.7% of 60,393 eligible beneficiaries (+0.1 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 42% of reported enrollment; 10 parent organizations have 11 or more members and the HHI is 2,724 (highly concentrated). For 2027, 2,231 members here are in plans that terminate or leave the county, and Health Care Service Corporation leaves. MA plans offered go from 49 to 38.
Parent organizations in Madison County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 14,039 | +447 | 41.9% |
| CVS Health Corporation | 8,120 | −2,366 | 24.2% |
| Humana Inc. | 4,738 | +1,547 | 14.1% |
| Lumeris Group Holdings Corporation | 4,386 | +584 | 13.1% |
| Centene Corporation | 954 | +28 | 2.8% |
| Devoted Health, Inc. | 674 | +587 | 2.0% |
| Molina Healthcare, Inc. | 377 | −30 | 1.1% |
| Health Care Service Corporation | 153 | −34 | 0.5% |
| Elevance Health, Inc. | 74 | −4 | 0.2% |
| Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 16 | 0 | under 0.1% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 7,654 beneficiaries in Madison County were assigned to 85 Medicare Shared Savings Program ACOs, 37.7% of assignable Original Medicare beneficiaries. Together, roughly 72% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.