Medicare Advantage in Cook County, Illinois
403,219 people in Cook County, Illinois were enrolled in Medicare Advantage in October 2026, 44.9% of 898,120 eligible beneficiaries (−0.01 pts since October 2025). Humana Inc. is the largest parent organization with 37% of reported enrollment; 19 parent organizations have 11 or more members and the HHI is 2,283 (highly concentrated). For 2027, 12,259 members here are in plans that terminate or leave the county. MA plans offered go from 58 to 48.
Parent organizations in Cook County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| Humana Inc. | 147,976 | +25,508 | 36.8% |
| CVS Health Corporation | 82,500 | −2,226 | 20.5% |
| UnitedHealth Group, Inc. | 76,127 | −1,398 | 18.9% |
| Health Care Service Corporation | 38,366 | −16,539 | 9.5% |
| Centene Corporation | 25,181 | −2,204 | 6.3% |
| Zing Health Consolidator, Inc | 14,388 | +1,293 | 3.6% |
| Devoted Health, Inc. | 6,662 | +1,817 | 1.7% |
| Molina Healthcare, Inc. | 4,095 | +1,454 | 1.0% |
| Lumeris Group Holdings Corporation | 2,181 | +1,317 | 0.5% |
| Union Health Services, Inc. | 1,527 | +4 | 0.4% |
| Elevance Health, Inc. | 792 | −20 | 0.2% |
| Longevity Health Founders, LLC | 762 | −34 | 0.2% |
| Rifkin Managed Care Holding, LLC | 714 | −110 | 0.2% |
| Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 449 | −11 | 0.1% |
| Highmark Health | 71 | +45 | 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, 127,994 beneficiaries in Cook County were assigned to 331 Medicare Shared Savings Program ACOs, 38.5% of assignable Original Medicare beneficiaries. Together, roughly 66% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.