Treasury Secretary Janet L. Yellen told Congress on Friday that on Jan. 21 the Treasury Department will have to begin using “extraordinary measures” to prevent the United States from defaulting on its debt.
The warning was likely one of Ms. Yellen’s final acts as Treasury secretary before the Trump administration assumes power at noon on Monday.
The debt limit — which caps the amount of money that the United States is authorized to borrow to fund the government and meet its financial obligations — will now be the problem of the next Treasury secretary, along with President-elect Donald J. Trump and the lawmakers who must decide its fate.
Mr. Trump has tapped Scott Bessent, a billionaire hedge fund manager, to lead the Treasury Department. The job requires Senate confirmation.
In her letter, Ms. Yellen sought to remind lawmakers that the debt limit simply allows the government to pay for spending that Congress has already approved.
“The debt limit does not authorize new spending, but it creates a risk that the federal government might not be able to finance its existing legal obligations that Congresses and presidents of both parties have made in the past,” Ms. Yellen said in the letter. “I respectfully urge Congress to act promptly to protect the full faith and credit of the United States.”