Some major insurers in the Affordable Care Act exchanges are expanding into new counties for 2027, even as many of their peers run for the exit amid ongoing cost and policy turbulence.
Centene, the largest ACA insurer in the U.S., is expanding into 55 additional counties in Alabama, Iowa, Illinois, Louisiana, Michigan, New Jersey and Texas next year; while Oscar Health, one of the fastest-growing carriers in the exchanges, is adding 140 new counties, including by entering South Carolina for the first time.
The changes, announced in press releases Tuesday, show a continued bet on the ACA among some major participants in the exchanges, which may see a growth opportunity as their competitors downsize and leave their members looking for new carriers.
Oscar, which covers about 2.9 million ACA enrollees, is currently in the middle of a major multi-year expansion in the ACA exchanges. The company plans to add between 400 and 600 new counties by 2029, fueled by record profits in the first half of this year, executives said during an investor day last month.
In Centene’s case, the county additions paper over the company’s decision to exit two states next year as it refocuses on more profitable markets.
Centene, which covers more than 3.5 million people on the ACA exchanges, is no longer offering Marketplace plans in Delaware or New Hampshire next year. Accordingly, the 55 new counties it’s adding for 2027 don’t represent a net change to Centene’s geographic footprint for 2027. A spokesperson did not respond to a request for county-level details.
Similarly, UnitedHealthcare, the largest private insurer in the U.S. with a significant presence in the ACA, is shutting down its ACA plans in Georgia next year — but the company’s footprint of about 1,300 counties is unchanged, suggesting it’s expanding in its remaining 29 states.
A spokesperson confirmed that UnitedHealthcare has added counties in some states, so the total is similar.
“We will continue to carefully evaluate exchanges on a state-by-state basis each year to assess future opportunities as this market matures and develops,” Eric Hausman, UnitedHealth’s vice president of media relations, said.
Two other major ACA insurers — Health Care Service Corporation, which offers marketplace coverage in five states, and GuideWell, a major Florida operator with plans in each of the state’s 67 counties — made no changes to their footprints for 2027, according to spokespeople for both companies.
Elevance and Kaiser Permanente did not respond to a request for information on their 2027 plans.
Insurers are repositioning after a difficult year in the exchanges. More generous subsidies for ACA coverage expired at the end of 2025, sending enrollment plummeting. As of June, ACA enrollment had fallen by more than 4.6 million people, according to the KFF — a steeper decline than most market watchers expected, as Americans, facing sky-high monthly costs for coverage, dropped out of the exchanges in droves as the year progressed.
That’s resulted in a smaller and apparently sicker risk pool, given healthier people are more likely to drop coverage, which is expected to raise spending for insurers. At the same time, Trump administration policies aimed at reducing fraud in the exchanges have caused legitimate enrollees to lose coverage and created additional uncertainty in the markets.
Many insurers are deciding it’s just not worth the hassle: Roughly a dozen carriers have said they plan to exit the ACA marketplaces after this year, in some or all states they operate.
The exits, among Cigna Healthcare, Baylor Scott & White, CareSource, Providence Health Plan, Molina and others, are set to affect hundreds of thousands of enrollees across multiple states.
Those remaining are asking for double-digit rate increases for the second year in a row, proposing a median 15% rate increase for 2027. It’s the highest back-to-back rate increase in the marketplace since 2018, according to the Commonwealth Fund.
Insurers are also reshaping their plans, including by making them more personalized — betting that plans targeted at individuals’ specific needs, including chronic disease management, will attract more members and help control medical spending.
Centene, which offers ACA coverage through its Ambetter subsidiary, is rolling out condition-specific plans, including for congestive heart failure, diabetes and asthma, that are deeply popular with members, the insurer said in its Tuesday release.
Centene will also continue offering round-the-clock virtual care, rewards programs for members completing health activities and discounts at partners including Walgreens and the YMCA.
Meanwhile, Oscar is introducing a plan aimed at helping early retirees transition from ACA coverage into Medicare, the company said. Oscar is also expanding plans targeted at women going through menopause, along with concierge care and discounts at Hy-Vee supermarket stores.
Open enrollment for 2027 ACA plans begins Nov. 1 in most states.
