Medicare Advantage in St. Louis County, Missouri
131,479 people in St. Louis County, Missouri were enrolled in Medicare Advantage in October 2026, 57.8% of 227,630 eligible beneficiaries (+0.1 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 43% of reported enrollment; 12 parent organizations have 11 or more members and the HHI is 2,647 (highly concentrated). For 2027, 3,177 members here are in plans that terminate or leave the county. MA plans offered go from 46 to 46.
Parent organizations in St. Louis County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 55,883 | −2,501 | 42.6% |
| CVS Health Corporation | 24,059 | −3,370 | 18.3% |
| Lumeris Group Holdings Corporation | 21,591 | +422 | 16.4% |
| Humana Inc. | 18,732 | +8,618 | 14.3% |
| Elevance Health, Inc. | 6,147 | −1,598 | 4.7% |
| Devoted Health, Inc. | 1,796 | +1,092 | 1.4% |
| Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 1,133 | −25 | 0.9% |
| Health Care Service Corporation | 985 | +90 | 0.8% |
| Centene Corporation | 725 | +13 | 0.6% |
| Mitchell Family Office | 135 | −30 | 0.1% |
| Missouri Healthcare Advisors, LLC | 53 | +17 | under 0.1% |
| Midwest Christian Villages, Inc. | 53 | +22 | 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, 41,441 beneficiaries in St. Louis County were assigned to 177 Medicare Shared Savings Program ACOs, 58.9% of assignable Original Medicare beneficiaries. Together, roughly 83% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.