Medicare Advantage in New Castle County, Delaware
40,011 people in New Castle County, Delaware were enrolled in Medicare Advantage in October 2026, 33.7% of 118,712 eligible beneficiaries (−0.1 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 34% of reported enrollment; 13 parent organizations have 11 or more members and the HHI is 2,388 (highly concentrated). For 2027, 994 members here are in plans that terminate or leave the county. MA plans offered go from 23 to 23.
Parent organizations in New Castle County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 13,638 | +242 | 34.2% |
| CVS Health Corporation | 11,958 | +572 | 30.0% |
| Highmark Health | 5,972 | −1,922 | 15.0% |
| Humana Inc. | 2,508 | +227 | 6.3% |
| Centene Corporation | 1,984 | +1,200 | 5.0% |
| Health Care Service Corporation | 1,604 | −429 | 4.0% |
| Independence Health Group, Inc. | 790 | +438 | 2.0% |
| Devoted Health, Inc. | 665 | new | 1.7% |
| Elevance Health, Inc. | 374 | −70 | 0.9% |
| Trinity Health Corporation | 290 | −4 | 0.7% |
| CareFirst, Inc. | 17 | new | under 0.1% |
| Horizon Mutual Holdings, Inc | 14 | −3 | under 0.1% |
| EmblemHealth, Inc. | 11 | 0 | 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, 37,894 beneficiaries in New Castle County were assigned to 183 Medicare Shared Savings Program ACOs, 65.3% of assignable Original Medicare beneficiaries. Together, roughly 77% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.