Medicare Advantage in Marlboro County, South Carolina
3,987 people in Marlboro County, South Carolina were enrolled in Medicare Advantage in October 2026, 60.7% of 6,565 eligible beneficiaries (+0.9 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 45% of reported enrollment; 7 parent organizations have 11 or more members and the HHI is 3,732 (highly concentrated). HRSA classifies the county as fully rural. For 2027, 123 members here are in plans that terminate or leave the county. MA plans offered go from 32 to 33.
Parent organizations in Marlboro County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 1,786 | −266 | 45.3% |
| Humana Inc. | 1,578 | +362 | 40.0% |
| CVS Health Corporation | 302 | −84 | 7.7% |
| Centene Corporation | 132 | +21 | 3.3% |
| BlueCross BlueShield of South Carolina (BCBSSC) | 101 | +34 | 2.6% |
| Molina Healthcare, Inc. | 24 | −1 | 0.6% |
| Independence Health Group, Inc. | 19 | −4 | 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, 901 beneficiaries in Marlboro County were assigned to 19 Medicare Shared Savings Program ACOs, 45.8% of assignable Original Medicare beneficiaries. Together, roughly 79% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.