Medicare Advantage in St. Johns County, Florida
31,106 people in St. Johns County, Florida were enrolled in Medicare Advantage in October 2026, 38.4% of 81,047 eligible beneficiaries (−0.5 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 37% of reported enrollment; 12 parent organizations have 11 or more members and the HHI is 2,838 (highly concentrated). For 2027, 4,825 members here are in plans that terminate or leave the county. MA plans offered go from 44 to 38.
Parent organizations in St. Johns County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 11,513 | +585 | 37.2% |
| Humana Inc. | 10,141 | +997 | 32.7% |
| CVS Health Corporation | 5,459 | −143 | 17.6% |
| Guidewell Mutual Holding Corporation | 2,558 | −667 | 8.3% |
| Elevance Health, Inc. | 326 | +23 | 1.1% |
| Devoted Health, Inc. | 316 | +227 | 1.0% |
| Centene Corporation | 309 | +16 | 1.0% |
| Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 222 | −9 | 0.7% |
| Highmark Health | 47 | +9 | 0.2% |
| Health Care Service Corporation | 40 | −7 | 0.1% |
| Horizon Mutual Holdings, Inc | 19 | new | under 0.1% |
| CareFirst, Inc. | 15 | +4 | 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, 20,865 beneficiaries in St. Johns County were assigned to 259 Medicare Shared Savings Program ACOs, 56.2% of assignable Original Medicare beneficiaries. Together, roughly 73% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.