Health Care Service Corporation in Illinois: 52,590 Medicare Advantage members, 6.5% share, 4th of 11.
Health Care Service Corporation lost 9,987 members (−16.0%) from Nov 2025 to Oct 2026 and stepped −14.9% at the 2026 election period against the market's +8.0%. It sells in 63 of Illinois’s 102 counties with visible members and leads 0; UnitedHealth sits just ahead at 20.9%, Centene just behind at 5.9%.
Health Care Service Corporation's twelve months in Illinois
Visible members each month, Nov 2025 to Oct 2026. The December-to-January step is the election period. The market line for the state is on the Illinois page.
Where Health Care Service Corporation's Illinois members are
The carrier’s five largest counties by visible members, with its share of each county’s visible Medicare Advantage members. It sells in 63 counties and leads 0 of them.
| County | Health Care Service Corporation members | Share of county | County visible members | County leader |
|---|---|---|---|---|
| Cook | 31,160 | 9.5% | 327,723 | Humana |
| DuPage | 5,429 | 10.4% | 52,312 | Humana |
| Will | 3,791 | 10.3% | 36,623 | Humana |
| Kane | 3,168 | 11.4% | 27,811 | Humana |
| Lake | 1,824 | 5.2% | 35,036 | Humana |
Health Care Service Corporation against the Illinois market
The carrier’s figures beside the state’s, each weighted by members. A difference is a difference, not a grade: a higher maximum or a lower rating is a design and a result, read in context.
top three hold 79.6%
market 3.91, −0.76, 6th of 6 rated
market 88%, −26 points
market $5,000, −$550
| # | Carrier | Members | Share | Twelve months | Election step | Counties led | Rating | $0 premium |
|---|---|---|---|---|---|---|---|---|
| 1 | Humana | 300,815 | 37.2% | +34.6% | +25.3% | 30 of 101 | 4.10 | 99% |
| 2 | Aetna (CVS) | 173,848 | 21.5% | +10.1% | +5.6% | 40 of 102 | 3.96 | 75% |
| 3 | UnitedHealth | 169,348 | 20.9% | −0.8% | −3.2% | 32 of 100 | 3.98 | 79% |
| 4 | Health Care Service Corporation | 52,590 | 6.5% | −16.0% | −14.9% | 0 of 63 | 3.15 | 61% |
| 5 | Centene | 47,722 | 5.9% | +36.4% | +32.2% | 0 of 89 | 3.19 | 100% |
| 6 | Zing Health Consolidator, Inc | 19,412 | 2.4% | +12.2% | −7.8% | 0 of 12 | 3.50 | 100% |
What 2027 does to Health Care Service Corporation's plans in Illinois
The fate assigned to each of the carrier’s plans for 2027, joined to the members in it today.
19,749 members are in 13 plans that end and must choose again. 32,841 members are in 6 plans that drop at least one county; which counties is not stated. In all, 100% of Health Care Service Corporation’s Illinois members are in a plan whose service area or status changes.
The read on Health Care Service Corporation in Illinois is in Carrier Command.
Risk and rebate against the market, the five-test read on coding versus selection, Stars levers and next year's cut points, the election-period forecast and the county-by-county standing, written as a monthly page.
Health Care Service Corporation elsewhere, and the rest of Illinois
- Humana37.2%
- Aetna (CVS)21.5%
- UnitedHealth20.9%
- Centene5.9%
- Zing Health Consolidator, Inc2.4%
How these numbers are made
- Members are visible members: CMS suppresses any plan-county cell of ten or fewer, so small counties undercount. Market share excludes employer group plans.
- Enrollment is Oct 2026; the twelve months run Nov 2025 to Oct 2026; the election step compares December 2025 with January 2026.
- Health Care Service Corporation is the parent organization Health Care Service Corporation; its 19 plans in Illinois may sell under other brand names. The rating is the 2027 overall Star Rating of its contracts weighted by members in Illinois; $0 premium and the in-network maximum are the 2027 filings weighted by members today.
- Plan fates are the ones assigned for contract year 2027.
- Every figure comes from public CMS data as Livmor reads it, and the page is rebuilt when a new month posts. Livmor Carrier Command, public CMS data.