Citing lower than expected tax revenues, both Treasury Secretary Janet Yellen and the Congressional Budget Office say that the U.S. government could run out of money by early June, moving up the deadline for President Biden to strike a deal with Congressional Republicans to raise the debt ceiling.

Yellen, in a Monday letter to House Speaker Kevin McCarthy, wrote, “After reviewing recent federal tax receipts, our best estimate is that we will be unable to continue to satisfy all of the government’s obligations by early June, and potentially as early as June 1, if Congress does not raise or suspend the debt limit before that time.”

The CBO released a similar conclusion. “Because tax receipts through April have been less than the Congressional Budget Office anticipated in February, we now estimate that there is a significantly greater risk that the Treasury will run out of funds in early June,” director Phillip Swagel wrote in a blog post.

Previously, the CBO had projected that the nation would run out of funds at some point between July and September.

Both Yellen and the CBO note that this projection is based on data currently available, but the actual date could vary if the underlying mix of revenues and spending materially changes.