More than $175 billion in U.S. tariff collections are at risk of being refunded now that the U.S. Supreme Court has ruled against President Donald Trump's broad emergency tariffs, Penn-Wharton Budget Model economists said Friday.
Their estimate, produced at Reuters’ request ahead of the ruling, was derived from a ground-up forecasting model using tariff rates by product and country for specific duties imposed by Trump, including those under the International Emergency Economic Powers Act (IEEPA).
Lysle Boller, senior economist for the non-partisan Penn-Wharton Budget Model (PWBM) at the University of Pennsylvania, said the model calculates revenue based on detailed import data.
The Supreme Court ruled Friday that the International Emergency Economic Powers Act (IEEPA) does not authorize a president to impose sweeping tariffs, delivering a major rebuke to President Donald Trump's use of emergency powers to reshape U.S. trade policy.
With the tariffs now struck down, importers are expected to seek refunds from U.S. Customs and Border Protection for duties paid over the past year.
Trump has touted the revenue from his tariffs, which the Congressional Budget Office estimates at about $300 billion annually over the next decade.
Refunds of $175 billion would exceed the combined fiscal 2025 budgets of the Department of Transportation, at $127.6 billion, and the Department of Justice, at $44.9 billion.
Boller said the PWBM model, built for long-term forecasts, cross-references U.S. Census Bureau import data covering about 11,000 product categories across 233 countries.
It applies statistical forecasting methods to estimate roughly $500 million in IEEPA-based revenue collected daily.
As of Thursday, the model estimated $179 billion in total IEEPA receipts since Trump began imposing tariffs under that law in February 2025.
PWBM also extrapolated past CBP data on IEEPA duty assessments as a share of overall Treasury customs receipts, producing a similar estimate of $175 billion to $176 billion.
CBP last published its IEEPA-related customs assessments on December 14, showing $133.5 billion at risk since the first duties were imposed.
Net duty collections are typically slightly lower because assessments are subject to adjustments and corrections that can result in refunds.
The model also adjusts quickly for abrupt tariff changes, including trade deals that reduce import duty rates for certain countries.
For example, South Korea’s U.S. tariff rate dropped to 15% from 25% in November.
The model captured other changes under IEEPA, such as a 40% tariff imposed last August on Brazil over the prosecution of Trump ally and former President Jair Bolsonaro.
It also reflected the removal of duties on Brazilian coffee, beef, and cocoa in November.
U.S. Treasury Secretary Scott Bessent told Reuters in January that the Treasury could easily cover any tariff refunds, though he is confident the Supreme Court will uphold the IEEPA tariffs.
The Treasury is planning to maintain large cash balances, targeting $850 billion at the end of March and $900 billion at the end of June.
In recent months, Treasury has reported customs receipts up roughly $20 billion per month compared with prior-year periods before the duties were imposed.
Total customs receipts reached about $27.7 billion in January.
Trump administration officials have said they would use alternative tariff authorities to reinstate tariffs if the court declares the IEEPA-based tariffs illegal.
© 2026 Thomson/Reuters. All rights reserved.