A shopper exits a Costco store in Centerville, Ohio, US, on Tuesday, Oct. 21, 2025.
Kyle Grillot | Bloomberg | Getty Images
Costco sued the Trump administration to get a full refund of new tariffs it paid so far this year, and to block those import duties from continuing to be collected from the retail warehouse club giant as a Supreme Court case plays out.
In the suit filed Friday, Costco said that it risks losing the money it has already paid to satisfy the tariffs even if the Supreme Court eventually upholds earlier lower court rulings that found President Donald Trump did not have the legal power to impose those duties.
The company noted a looming Dec. 15 deadline that could prevent the tariffs that it has already paid on an estimated basis from being refunded. Costco did not say how much money it believes should be refunded to the company.
Costco’s suit, filed in the U.S Court of International Trade, said that U.S. Customs and Border Protection denied the company’s request to extend the Dec. 15 date of so-called liquidation, the final computation of tariffs assessed on imported items.
While an importer has six months to file a protest contesting liquidation, “not all liquidations are protestable,” the suit said.
Dozens of other companies have filed similar lawsuits to protect their right to potential refunds in case the Supreme Court rules against the so-called reciprocal tariffs that Trump imposed on imports from many U.S. trading partners and his so-called fentanyl tariffs on products from Canada, China, and Mexico.
Trump invoked the International Emergency Economic Powers Act to impose those often high tariffs.
In August, the U.S. Court of Appeals for the Federal Circuit, in a 7-4 ruling, upheld a prior decision by the Court of International Trade that found Trump did not have that power.
“The core Congressional power to impose taxes such as tariffs is vested exclusively in the legislative branch by the Constitution,” the Federal Circuit said in its ruling. “Tariffs are a core Congressional power.”
During oral arguments on Nov. 5, a majority of the Supreme Court’s nine justices appeared skeptical of arguments by a lawyer for the Trump administration that the president did have the power to impose the tariffs.
The Supreme Court took the administration’s appeal of the lower court rulings on an expedited basis, but it is not clear when or how the court will decide the dispute.
Costco, in its lawsuit, said, “This separate action is necessary, however, because even if the IEEPA duties and underlying executive orders are held unlawful by the Supreme Court, importers that have paid IEEPA duties, including Plaintiff, are not guaranteed a refund for those unlawfully collected tariffs in the absence of their own judgment and judicial relief.”
“This Court and the Federal Circuit have cautioned that an importer may lack the legal right to recover refunds of duties for entries that have liquidated, even where the underlying legality of a tariff is later found to be unlawful,” the suit said.
White House spokesman Kush Desai, in a statement on Costco’s suit, said, “The economic consequences of the failure to uphold President Trump’s lawful tariffs are enormous and this suit highlights that fact.”
“The White House looks forward to the Supreme Court’s speedy and proper resolution of this matter,” Desai said.
CNBC has requested comment from Costco.
The Trump administration has warned of the potential fallout of having to refund hundreds of millions of dollars in tariffs if the Supreme Court upholds the lower court rulings that Trump did not have authority under IEEPA to unilaterally impose those duties.