1 million lose their ACA insurer. CMS sends 4 in 10 to Centene

Open enrollment for 2027 starts Nov 1. For 1,020,968 people, the company that sold them an ACA plan will not be there.

10 companies leave whole HealthCare.gov states for 2027. That is 25 company and state exits across the 29 states we checked. Those customers do not lose coverage on Jan 1 if they do nothing. CMS moves them into a plan from another company. The CMS file that does this is called the crosswalk.

We followed every one of those moves, county by county.

Chart: Health and Tech Now analysis of CMS files.

Where CMS sends them

By our estimate, 403,736 people go to Centene’s Ambetter. That is 39.5% of everyone leaving, about 4 in 10. Oscar gets 124,908. Florida Blue gets 108,584. Elevance gets 93,017, and Blue Cross plans run by HCSC get 69,101.

These are estimates. CMS publishes 2025 enrollment by company and county, and by plan statewide. It does not publish enrollment by plan and county, which is how the crosswalk works. So we weighted each plan by its 2025 members.

Counted the simpler way, one share per plan, Ambetter gets 338,333 and Oscar gets 191,863. Both counts are ours. We show both because the method changes Ambetter’s count by 65,403 people.

Why silver matters

The two methods differ because CMS often sends each metal tier to a different company in the same county.

Take Dallas County. Baylor Scott and White Health Plan is leaving Texas. CMS sends its 3 silver plans there to Ambetter, its gold plans to Oscar and its bronze plans to Blue Cross. Count plans and Ambetter gets 3 of 10 plans. But 78% of Baylor Scott and White’s 2025 members statewide were in silver plans. Across all 10 departing companies, 65.3% were in silver.

So weighting by members moves people toward Ambetter and away from Oscar.

Who is leaving

Molina has the most customers leaving, 352,189 in Florida, Mississippi, Ohio, South Carolina and Utah. Cigna follows with 250,666, in Arizona, Florida, Indiana, Mississippi, North Carolina, Tennessee and Texas. Baylor Scott and White has 223,380 in Texas. CareSource has 113,449 in Indiana, Ohio and West Virginia.

9,295 people live in counties where the crosswalk lists no 2027 plan for their company. They are 4,230 with Cox HealthPlans in Missouri, 3,163 with Molina in South Carolina and 1,902 with Molina in Utah. They need to pick a plan themselves.

Mississippi is hit hardest

44.7% of Mississippi’s 2025 HealthCare.gov enrollees were with Cigna and Molina, and both are leaving the state. That is 122,553 of 274,385 people. Next are New Hampshire at 39.5%, Ohio at 25.8% and West Virginia at 25.1%.

Counties down to one company

132 counties will have one insurer company selling ACA plans in 2027, up from 77 in 2026. 72 of them had two or more this year. 171,065 people enrolled in 2025 live in those 72 counties. By state, that is North Carolina 29, Texas 13, West Virginia 10, Mississippi 9, Indiana 7, Iowa 2 and Oklahoma 2.

No county in these states is left with zero companies.

What it means for you

If your insurer is leaving, you will be moved to a new plan unless you pick one. That plan may have a different price, network and drug list. Log in to HealthCare.gov and look at the plan you are set to get. Check that your doctors and drugs are covered, and compare the price after your subsidy. Pick a plan by Dec 15 for coverage that starts Jan 1. Open enrollment ends Jan 15. If you live in a county with one company, compare that company’s plans across metal levels.

How we did this

A company counts as leaving if it sold individual plans on HealthCare.gov in a state in 2026 and sells none there in 2027. We do not count partial exits inside a state. We used 29 states. Oregon is left out because it runs its own exchange for 2027. People are each company’s 2025 average monthly enrollment by county from CMS. CMS hides counts of 10 or fewer. We count those as zero, so every number is a floor. Where people go is an ESTIMATE. All other numbers are counts from CMS files.

We checked that everyone leaving is accounted for. Each person is sent to a company or listed with no plan row, and the difference is 0. CMS’s enrollment file gives the same total two ways, adding up counties and adding up companies. Both come to 1,020,968. CMS’s plan level sheet gives 1,021,303. The small gap comes from the cells CMS hides.