The Centers for Medicare and Medicaid Services, which administers programs under the Affordable Care Act, said the action affects $10.4 billion in risk adjustment payments.
President Donald Trump’s administration has used its regulatory powers to undermine Obamacare after the Republican-controlled Congress last year failed to repeal and replace the law. About 20 million Americans have received health insurance coverage through the program.
The payments are intended to help stabilize health insurance markets by compensating insurers that had sicker, more expensive enrollees in 2017. The government collects the money from health insurers with relatively healthy enrollees, who cost less to insure.
CMS, which is overseen by the U.S. Department of Health and Human Services, said the move was necessary because of a February ruling by a federal court in New Mexico, which found that the federal government was using an inaccurate formula for allocating the payments.