C.B.O. Warns of Possible Default Between July and September

WASHINGTON — The Treasury Department’s ability to continue paying its bills and prevent the United States from defaulting on its debt could be exhausted sometime between July and September if Congress does not raise or suspend the cap on how much the nation can borrow, the nonpartisan Congressional Budget Office said on Wednesday.

The estimate suggests that lawmakers could have slightly more leeway than Treasury Secretary Janet L. Yellen estimated last month, when she told Congress that her department’s ability to keep financing America’s obligations could be exhausted in June.

The United States borrows huge sums of money for funding that includes military salaries, retiree benefits and interest payments to bondholders who own U.S. debt. The nation hit its statutory $31.4 trillion borrowing cap last month, forcing the Treasury Department to employ a series of accounting maneuvers to help ensure the government can continue paying its bills without breaching the debt limit.

“If the debt limit is not raised or suspended before the extraordinary measures are exhausted, the government would be unable to pay its obligations,” the C.B.O. said in the report on Wednesday. “As a result, the government would have to delay making payments for some activities, default on its debt obligations or both.”

However, the budget office noted that the timing of the so-called X-date is uncertain because it depends on how much tax revenue comes into the federal government over the coming months. The office said that if receipts fall short of its estimates, the Treasury could run out of funds before July.

Ms. Yellen has been employing extraordinary measures since January to keep the government running. Those have included redeeming some existing investments and suspending new investments in the Civil Service Retirement and Disability Fund and the Postal Service Retiree Health Benefits Fund.

In a speech on Tuesday, Ms. Yellen warned that a default would be catastrophic.

“In my assessment — and that of economists across the board — a default on our debt would produce an economic and financial catastrophe,” Ms. Yellen said at the National Association of Counties Legislative Conference. “Household payments on mortgages, auto loans and credit cards would rise, and American businesses would see credit markets deteriorate.”

Calling on Congress to act, she added: “This economic catastrophe is preventable.”

It remains unclear how quick or easy it will be to raise or suspend the debt cap. Republican lawmakers have insisted that President Biden agree to undefined spending cuts in order to win their vote to raise the cap. Mr. Biden has insisted he will not negotiate spending cuts as part of any debt limit legislation, arguing that the cap has to be raised to fund obligations that Congress — including Republicans — already approved.

A separate C.B.O. report out on Wednesday showing the federal government will add $19 trillion in debt over the next decade and run $2 trillion annual deficits is likely to inflame those tensions.