$90 Billion. That’s roughly how much in IEEPA tariffs the federal government will have to return if the Supreme Court decides that the president cannot impose tariffs on countries under the International Emergency Economic Powers Act.

Refunds are actually common in the customs world. For instance, if a company accidentally pays too much in tariffs, it can ask Customs and Border Protection to give that money back.

“You have to provide the evidence that maybe you filed under the wrong code, and you feel like you’re owed a refund,” said Ryan Petersen, the CEO of Flexport, a supply chain management firm that helps companies request tariff refunds.

Petersen said the process normally takes six to nine months.

“It’ll depend on how good your case is, and if your paperwork is clear, if they sort of ask follow-up questions, and push on it, and stuff like that,” Petersen said.

So, if the government has to repay $90 billion worth of tariffs? The backlog could pile up.

“So, I think that the most likely approach would be like, alright, well there’s a legal process for this. Everyone get your receipts, find our forms, file the forms, dot all the Is, cross all the Ts,” said Rachel Brewster, a professor at Duke Law School.

Brewster said that takes time and resources.

“And you could imagine that for some small businesses who are really being hurt by the tariffs, the idea of hiring the lawyers or the accountants to put together the records to get that money back, might simply not be a cost-benefit proposition,” said Brewster.

Having to pay back all of those tariffs would also have consequences for the Treasury Department.

“The Treasury likely doesn’t have that type of money on hand,” said Lawrence Gillum, chief fixed income strategist at LPL Financial.

He said the government would likely raise that money by auctioning off short-term bonds.

“And then, you’d have to have market participants buy those treasuries, and kind of satisfy that new supply in the market,” Gillum said.

And demand for those bonds isn’t guaranteed.

“There’s been times where these auctions haven’t been great,” Gillum said. “And there’s been times when these auctions have been really great. So, it’s kind of hard to say, definitively, that this will go well.”

And if it doesn’t, the interest the government pays could rise.