For months, Trump has kept insurers guessing about whether his administration would continue to pay the subsidies. Some insurers have warned that without them, they would either raise rates or pull out of the Obamacare insurance exchanges, but others simply set their prices this year assuming they wouldn’t get the CSR payments.

The Congressional Budget Office previously estimated that premiums for middle-tier plans would rise by about 20 percent next year if the payments were discontinued, though many customers would be shielded from the hike by the Obamacare tax credits. The cost to the federal government, meanwhile, would be about $6 billion next year. (Obamacare's tax credits are tied to the premiums for silver plans, which would rise if CSR payments ended. Therefore, tax credits, which are also financed by the government, would also have to increase, more than offsetting the savings from the CSRs.) As one Kaiser Family Foundation report on the subsidies’ potential end put it, “This assumes that insurers would be willing to stay in the market if CSR payments are eliminated.”

The CBO said that for insurers, the uncertainty around the subsidies could be mitigated if they were discontinued through legislation, as opposed to unilaterally by the president. “Executive or judicial action could very well be challenged in lawsuits that would take some time to resolve—potentially extending the number of years insurers might not participate in the marketplaces,” the agency wrote.

Loren Adler, the associate director of the University of Southern California–Brookings Schaeffer Initiative on Health Policy, pointed out that the pain for insurers might be only temporary. “Insurers will likely win an injunction to continue CSR funding, in which case this is about temporary uncertainty and one-year premium hikes,” he wrote on Twitter.

Still, the added uncertainty is yet another way the Trump administration has subtly weakened Obamacare this year. Ending the CSR payments may very well be the thousandth cut; it remains to be seen if the Obamacare exchanges will stay alive despite it.