The largest U.S. health insurers are shrinking where they lose money and growing where they do not, and the result for 2027 is fewer Medicare Advantage plans, a thinner ACA Marketplace and a handful of companies moving the other way. Cigna is leaving the individual market in all 11 of its states, Centene is cutting 344 Medicare Advantage counties, and Oscar is adding 140 Marketplace counties.
Health Plan News has published profiles of the eight biggest names consumers see on their insurance cards, each with membership, 2027 plan changes, Medicaid contracts, claim denial rates and contact numbers. Start with UnitedHealthcare, the largest, or Anthem, the largest Blue Cross company.
If your insurer appears below with a cut in your market, check your 2027 plan notice now. Medicare Open Enrollment ends December 7.
Retreating From Medicare Advantage
UnitedHealthcare, the market leader, is discontinuing plans covering about 390,000 people for 2027 after losing about 840,000 Medicare Advantage members this year. Humana is exiting plans that cover about 600,000 members. Centene’s Wellcare is leaving about 20% of its counties, the steepest cut among public insurers, and Molina is dropping its standard Medicare Advantage drug plans entirely.
Star ratings moved in opposite directions. Humana says 95% of its members will be in plans rated 4 stars or higher for 2027, up from about 20%. UnitedHealthcare’s average rating fell to 3.57 and Elevance’s to 3.51.
Our Humana and Aetna profiles cover their 2027 plans and prior authorization records.
Leaving and Entering the ACA Marketplace
The Marketplace exits are larger. Cigna is leaving individual coverage in 11 states, affecting about 369,000 people, and Molina is going from 14 states to about seven. UnitedHealthcare is leaving Georgia. Aetna already left every exchange for 2026.
Oscar is the exception.
It is adding 140 counties and entering South Carolina, after growing its share within its service areas from 17% to 30% this year. Centene’s Ambetter, still the largest Marketplace insurer, is adding 55 counties and leaving Delaware and New Hampshire. See our Oscar and Ambetter profiles.
Why the Big Insurers Are Pulling Back
Medical costs have run ahead of premiums and government payments for two years. Medicare Advantage enrollees are using more care, and the ACA Marketplace lost healthier enrollees after the expanded premium tax credits expired. Centene posted a $6.7 billion loss for 2025, and Molina’s third-quarter profit fell by half.
Most companies are now earning more by shrinking. UnitedHealth, Elevance, CVS Health, Centene and Humana all raised 2026 earnings guidance in October. That is good for shareholders and harder on enrollees whose plans disappear.
What To Do Next
- Read your Annual Notice of Change or Marketplace renewal letter for 2027.
- If your plan is ending, choose a new one by December 7 for Medicare or December 15 for the Marketplace.
- Compare each insurer’s record in our claim denial rankings.
- Check which insurers lead your state on our market share by state page.
Profiles of Cigna and Molina are also available, along with our full List of Health Insurance Companies. Follow our Health Insurance Companies hub for more.