Spending by the federal government could increase by $2.3 billion if the Trump administration cuts off Obamacare payments that help insurers reduce out-of-pocket medical costs for poorer customers, according to a study released Tuesday by the Kaiser Family Foundation.

The legality of the payments, called “cost-sharing reduction subsidies,” was challenged under a House lawsuit brought against former President Barack Obama, and the case has been temporarily delayed. If a federal appeals court cancels the funds or the Trump administration drops an appeal on the case, insurers are expected to leave the exchanges as soon as they are able or increase premiums to make up for their losses.