Stocks of the biggest sellers of health insurance under the Affordable Care Act, also known as Obamacare, were hit hard Tuesday after Vice President JD Vance said the Trump administration has yanked coverage from more than 750,000 enrollees due to fraud.

The price of Centene stock was down nearly 3% while the share price of Oscar Health stock was down more than 4% on Tuesday in trading on the New York Stock Exchange. Oscar has 2.9 million health plan enrollees that are largely enrolled in Obamacare while Centene has 3.5 million enrolled in such marketplace coverage.

“We’re actually making sure that the people receiving Obamacare subsidies are actually entitled to receive them,” Vance said at a news conference Tuesday.

In a separate announcement, the Centers for Medicare & Medicaid Services (CMS), which administers government-subsidized health insurance coverage including Obamacare, said the Trump administration canceled “approximately 315,000 unauthorized enrollments covering more than 760,000 individuals, which is expected to result in a return of roughly $2.2 billion in taxpayer-funded subsidies.”

For their part, health insurance companies have been saying since last year that their dip in enrollment this year hasn’t been related to fraud. Rather, it’s because the Republican-led Congress and the Trump administration didn’t renew enhanced subsidies that make Obamacare more affordable.

For example, Centene’s marketplace enrollment dropped to 3.5 million at the end of the second quarter compared to 5.8 million in the second quarter of last year.

The big dip in Centene’s enrollment is what Democrats in Congress and health insurance industry analysts said would happen after Republicans in Congress and the Donald Trump White House wouldn’t agree to extend enhanced tax credits for buyers of Obamacare.

A KFF analysis last fall said middle income Americans “as well as those with low incomes” will see “major out-of-pocket premium increases” if tax credits aren’t extended. And they are with customers who reported a doubling and even tripling of premiums for this year. The subsidies, or tax credits, made health insurance premiums more affordable for individuals and were enhanced by the Biden administration and the Democratic-controlled Congress, which passed the Inflation Reduction Act of 2022, allowing more Americans to buy coverage.

Still, the Trump administration said it has established a “Federally-facilitated Exchange anti-fraud coordination group that brings together leadership from across CMS and the U.S. Department of Health and Human Services (HHS) to drive a unified, sustained response to fraud in the Federal Marketplace.” CMS said the group will meet regularly to “coordinate enforcement and program integrity efforts and maintain momentum in the fight to crush fraud in the FFE.”

“We are shutting down unauthorized Marketplace enrollments and returning approximately $2.2 billion in taxpayer-funded subsidies,” HHS Secretary Robert F. Kennedy, Jr. said in a statement. “CMS is strengthening safeguards, pursuing bad actors, and holding agents and brokers accountable when they break the rules. Under President Trump, HHS will protect Americans’ health coverage and ensure taxpayer dollars reach the people they are intended to serve.”