Medicare Advantage in Boone County, Illinois
5,844 people in Boone County, Illinois were enrolled in Medicare Advantage in October 2026, 51.6% of 11,321 eligible beneficiaries (−0.3 pts since October 2025). CVS Health Corporation is the largest parent organization with 46% of reported enrollment; 8 parent organizations have 11 or more members and the HHI is 3,179 (highly concentrated). For 2027, 108 members here are in plans that terminate or leave the county, and Health Care Service Corporation leaves. MA plans offered go from 37 to 26.
Parent organizations in Boone County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| CVS Health Corporation | 2,664 | −33 | 45.9% |
| Humana Inc. | 1,652 | +310 | 28.5% |
| UnitedHealth Group, Inc. | 893 | −144 | 15.4% |
| Zing Health Consolidator, Inc | 177 | +45 | 3.1% |
| Health Care Service Corporation | 120 | −66 | 2.1% |
| Devoted Health, Inc. | 118 | +101 | 2.0% |
| Centene Corporation | 96 | −31 | 1.7% |
| Molina Healthcare, Inc. | 81 | +11 | 1.4% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 1,616 beneficiaries in Boone County were assigned to 37 Medicare Shared Savings Program ACOs, 41.4% 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.