ACA Insurers Face Enrollment Declines Amid Fraud Crackdown And Subsidy Expiration

Shares of major health insurers that sell Affordable Care Act coverage fell after Vice President JD Vance announced that the Trump administration had removed more than 750,000 people from ACA coverage over what officials described as unauthorized enrollments.

Health insurance information is displayed on a computer screen. ACA insurers are facing enrollment changes following the expiration of enhanced subsidies and new federal enforcement actions.

Centene shares fell nearly 3%, while Oscar Health shares fell more than 5% during Tuesday trading, according to Forbes. 

Oscar had about 2.9 million members in individual coverage, while Centene reported 3.49 million Marketplace members at the end of the second quarter.

CMS separately said it canceled approximately 315,000 unauthorized enrollments covering more than 760,000 individuals. The agency expects the cancellations to return roughly $2.2 billion in taxpayer-funded advance premium tax credits.

The enforcement action comes as insurers are also dealing with a broader decline in ACA Marketplace enrollment following the expiration of enhanced premium tax credits at the end of 2025.

Centene reported 3.49 million Marketplace members at the end of the second quarter, down from 5.86 million a year earlier.

The company has previously cited changes in Marketplace membership and pricing as factors affecting its business.

The expiration of the enhanced subsidies has been identified by insurers and health-policy analysts as a major factor behind enrollment declines in 2026.

The enhanced credits, first enacted during the COVID-19 pandemic and subsequently extended through 2025, made Marketplace coverage more affordable for many consumers.

The latest CMS action is distinct from those broader enrollment changes.

The agency says it is specifically targeting enrollments it has determined were unauthorized after reviews involving insurers and federal officials.

CMS said it has also targeted agents and brokers, including 569 who received notices of intent to terminate their Exchange agreements after submitting applications without required applicant information.