Medicare Advantage in Williamsburg County, South Carolina
5,304 people in Williamsburg County, South Carolina were enrolled in Medicare Advantage in October 2026, 61.3% of 8,657 eligible beneficiaries (+1.1 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 53% of reported enrollment; 10 parent organizations have 11 or more members and the HHI is 3,496 (highly concentrated). HRSA classifies the county as fully rural. For 2027, 173 members here are in plans that terminate or leave the county. MA plans offered go from 44 to 44.
Parent organizations in Williamsburg County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 2,809 | −470 | 53.4% |
| Humana Inc. | 1,199 | +226 | 22.8% |
| CVS Health Corporation | 390 | −11 | 7.4% |
| Devoted Health, Inc. | 305 | new | 5.8% |
| Centene Corporation | 285 | −15 | 5.4% |
| Health Care Service Corporation | 96 | +43 | 1.8% |
| Clover Health Holdings, Inc. | 70 | +53 | 1.3% |
| Molina Healthcare, Inc. | 53 | −1 | 1.0% |
| Independence Health Group, Inc. | 27 | −3 | 0.5% |
| Elevance Health, Inc. | 26 | +2 | 0.5% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 922 beneficiaries in Williamsburg County were assigned to 21 Medicare Shared Savings Program ACOs, 34.4% of assignable Original Medicare beneficiaries. Together, roughly 75% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.