Republicans are demanding that the Biden administration exercise greater oversight of the massive expansion of Obamacare premium tax credits enacted as part of President Joe Biden’s pandemic relief legislation, a boost that federal budget experts say will cost taxpayers nearly $45 billion.

“The U.S. Government Accountability Office has found that these subsidies are susceptible to significant improper payments,” 28 Republicans told the administration in a letter exclusively obtained by the Washington Examiner. “With the federal deficit projected to grow to record levels this year, fiscal accountability has never been more important.”