Medicare Advantage in Winnebago County, Illinois
37,662 people in Winnebago County, Illinois were enrolled in Medicare Advantage in October 2026, 58.7% of 64,155 eligible beneficiaries (+0.02 pts since October 2025). CVS Health Corporation is the largest parent organization with 50% of reported enrollment; 12 parent organizations have 11 or more members and the HHI is 3,369 (highly concentrated). For 2027, 604 members here are in plans that terminate or leave the county, and Health Care Service Corporation leaves. MA plans offered go from 38 to 26.
Parent organizations in Winnebago County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| CVS Health Corporation | 18,926 | +218 | 50.4% |
| Humana Inc. | 9,576 | +1,685 | 25.5% |
| UnitedHealth Group, Inc. | 4,472 | −940 | 11.9% |
| Zing Health Consolidator, Inc | 1,898 | +326 | 5.1% |
| Devoted Health, Inc. | 871 | +743 | 2.3% |
| Centene Corporation | 699 | −180 | 1.9% |
| Molina Healthcare, Inc. | 508 | +33 | 1.4% |
| Health Care Service Corporation | 447 | −117 | 1.2% |
| Rifkin Managed Care Holding, LLC | 89 | −23 | 0.2% |
| Highmark Health | 33 | −2 | under 0.1% |
| Elevance Health, Inc. | 23 | −1 | under 0.1% |
| Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 17 | +6 | 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, 9,061 beneficiaries in Winnebago County were assigned to 106 Medicare Shared Savings Program ACOs, 46.6% of assignable Original Medicare beneficiaries. Together, roughly 78% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.