Medicare Advantage in Nassau County, Florida
12,967 people in Nassau County, Florida were enrolled in Medicare Advantage in October 2026, 42.5% of 30,501 eligible beneficiaries (−0.3 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 51% of reported enrollment; 9 parent organizations have 11 or more members and the HHI is 3,488 (highly concentrated). For 2027, 1,172 members here are in plans that terminate or leave the county. MA plans offered go from 34 to 33.
Parent organizations in Nassau County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 6,561 | +194 | 50.9% |
| Humana Inc. | 2,914 | +223 | 22.6% |
| CVS Health Corporation | 2,475 | −35 | 19.2% |
| Guidewell Mutual Holding Corporation | 310 | −71 | 2.4% |
| Centene Corporation | 283 | +8 | 2.2% |
| Elevance Health, Inc. | 165 | +17 | 1.3% |
| Devoted Health, Inc. | 120 | +49 | 0.9% |
| Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 41 | −2 | 0.3% |
| Highmark Health | 13 | 0 | 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, 4,430 beneficiaries in Nassau County were assigned to 152 Medicare Shared Savings Program ACOs, 33.9% of assignable Original Medicare beneficiaries. Together, roughly 62% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.