Medicare Advantage in Los Alamos County, New Mexico
556 people in Los Alamos County, New Mexico were enrolled in Medicare Advantage in October 2026, 14.5% of 3,831 eligible beneficiaries (+0.1 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 37% of reported enrollment; 6 parent organizations have 11 or more members and the HHI is 2,827 (highly concentrated). HRSA classifies the county as fully rural. For 2027, 121 members here are in plans that terminate or leave the county, and CHRISTUS Health leaves. MA plans offered go from 18 to 13.
Parent organizations in Los Alamos County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 200 | −2 | 37.4% |
| Health Care Service Corporation | 147 | 0 | 27.5% |
| Humana Inc. | 135 | +4 | 25.2% |
| Presbyterian Healthcare Services | 27 | −1 | 5.0% |
| CHRISTUS Health | 14 | +1 | 2.6% |
| CVS Health Corporation | 12 | +1 | 2.2% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 109 beneficiaries in Los Alamos County were assigned to 23 Medicare Shared Savings Program ACOs, 4.4% of assignable Original Medicare beneficiaries. Together, roughly 18% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.