Medicare Advantage in Mason County, Michigan
6,417 people in Mason County, Michigan were enrolled in Medicare Advantage in October 2026, 66.8% of 9,609 eligible beneficiaries (+1.0 pts since October 2025). Corewell Health is the largest parent organization with 48% of reported enrollment; 7 parent organizations have 11 or more members and the HHI is 3,189 (highly concentrated). HRSA classifies the county as partly rural. For 2027, 2,592 members here are in plans that terminate or leave the county. MA plans offered go from 39 to 35.
Parent organizations in Mason County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| Corewell Health | 3,048 | +282 | 47.9% |
| Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 1,711 | −366 | 26.9% |
| Humana Inc. | 611 | +76 | 9.6% |
| CVS Health Corporation | 457 | +53 | 7.2% |
| UnitedHealth Group, Inc. | 320 | +9 | 5.0% |
| Trinity Health Corporation | 117 | +68 | 1.8% |
| Henry Ford Health System | 103 | +91 | 1.6% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 2,120 beneficiaries in Mason County were assigned to 33 Medicare Shared Savings Program ACOs, 80.6% of assignable Original Medicare beneficiaries. Together, roughly 94% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.