When will the US run out of money? The answer is complicated.

In letters to Congress and warnings to corporate leaders about the catastrophic consequences if the United States defaults on its debts, Treasury Secretary Janet L. Yellen has repeatedly made important reservations.

She cannot give the exact date when the federal government will run out of money.

The United States hit its $31.4 trillion statutory debt limit on Jan. 19, forcing the Treasury Department — which borrows huge sums of money to pay the country’s bills — to use accounting maneuvers known as extraordinary measures to save cash and avoid going over the limit.

On Monday, Ms Yellen reiterated earlier warnings that the Treasury Department could deplete its cash reserves by June 1. Yet it is almost impossible to determine the exact day when the United States will reach the so-called X date.

“These estimates are based on currently available data, and federal revenues, expenditures and debts may differ from these estimates,” Ms. Yellen told lawmakers in her letters. “The actual date when the Treasury exhausts extraordinary measures may be several days or weeks later than these estimates.”

Although Treasury has the most sophisticated cash management system in the world and employs teams of highly trained economists, the treasury is a blur of payments going out and tax revenue coming in. with which the General Account of the Treasury started the day less than $100 billion – locating the X-date becomes even more difficult to predict. In many ways, this is because the point at which a default would occur is a moving target.

Big bills are coming.

Ms. Yellen sees early June as a pivotal month since her first warnings to Congress about the debt limit in January. The reason: The federal government spends a lot of money in a short period of time around June 1, and it’s impossible to predict exactly how much revenue will come in and when.

In a report published Thursday, the Bipartisan Policy Center, a think tank that closely monitors federal spending, estimated that the government would spend $101 billion on June 1. be targeted at veterans’ benefits, military pay and retirement, civil service retirement, and supplemental security income. By June 2, the government must pay $25 billion in Social Security benefits and another $2 billion in Medicaid.

During those two days, the government is expected to spend about $140 billion and collect only $44 billion in tax revenue, putting steam on the country’s treasury.

Revenues are sputtering while repayments are flowing.

A major problem this year is that tax revenues are coming in slower than expected.

Severe storms, flooding and mudslides in California, Alabama and Georgia this year prompted the Internal Revenue Service to extend tax filing deadlines from April 18 to October in dozens of counties.

Another surprising reason the money is turning out lower than some budget experts predicted is that the IRS is starting to work more efficiently. As a result of the $80 billion the agency received last year as part of the Inflation Reduction Act, it has been able to ramp up hiring and clear the backlog of unprocessed tax returns.

Because the IRS has processed returns faster, refunds are also paid out faster and the available amount of cash is emptied.

June 15 is a critical day.

If Ms. Yellen can find enough coins in the Treasury bank to pay the bills through June 15, the United States could get a little breathing room.

That’s because on June 15, third-quarter payments are due from businesses and people who must pay their tax bills throughout the year or choose to make payments every three months to avoid paying big bills in April.

The Congressional Budget Office said in a report last week that an expected inflow of quarterly tax revenues on June 15 and the availability of additional extraordinary measures would likely allow the government to continue funding operations at least through the end of July.

The government could receive about $80 billion in tax revenue that day. The Bipartisan Policy Center estimates that those funds could be enough to keep the federal government afloat until June 30. At that point, Ms. Yellen would also have some additional extraordinary measures at her disposal — a suspension of investment in federal employee pension funds — that would allow her to unlock another $145 billion and potentially delay a default well into the future. in July.

It’s too close to call.

The lack of clarity on the X date has made it difficult for lawmakers to know the pressure they’re under to make a deal. The government may not know how quickly the money will run out until just before the country defaults.

But the pressure is still mounting. Congress will likely take days — if not weeks — to pass legislation to raise the debt ceiling. And even if President Biden and Speaker Kevin McCarthy reach an agreement, there is no guarantee that the House and Senate will easily pass the legislation.

The legislative calendar becomes increasingly complex as summer approaches.

Mr. McCarthy and Senator Chuck Schumer, New York Democrat and Majority Leader, would have to push legislation reflecting that agreement through their respective chambers, and the days left to do so are rapidly dwindling. The House is scheduled to sit just six days before the end of the month. The Senate is set at just five people and is expected to leave Washington beginning Monday before Memorial Day weekend.

Aware that lawmakers hate having to reschedule their breaks, analysts have been keeping a close eye on the legislative schedule as they try to read the debt limit tea leaves. Failing to sign a deal by Memorial Day and Ms. Yellen not announcing that the X date has been postponed could increase the likelihood of a short-term suspension of the borrowing ceiling to give Congress more time to act.

“The congressional calendar is king and will dictate urgency and passage dates for a bill, as has historically been the case,” said Henrietta Treyz, the director of economic policy at Veda Partners, in a note to clients this month.