Costco filed a lawsuit against the Trump administration seeking a full refund of tariffs it has already paid this year and to prevent further collection of those import duties while a related Supreme Court case proceeds.
The suit, submitted to the U.S. Court of International Trade on Friday, argues that Costco could lose the money it paid in tariffs even if the Supreme Court ultimately rules that the duties were imposed unlawfully. The company highlighted a Dec. 15 deadline for “liquidation,” the final computation of tariffs on imported goods, which could prevent refunds of amounts already paid. Costco did not specify the total refund it is seeking.
According to the lawsuit, U.S. Customs and Border Protection denied the company’s request to extend the liquidation date. The suit notes that although importers have six months to protest a liquidation, “not all liquidations are protestable.”
Costco joins dozens of other companies pursuing similar legal actions to protect their right to refunds in the event the Supreme Court rules against tariffs imposed under President Donald Trump. These include so-called reciprocal tariffs on goods from U.S. trading partners and additional duties on certain products from Canada, China, and Mexico. Trump had used the International Emergency Economic Powers Act (IEEPA) to justify the tariffs.
In August, the U.S. Court of Appeals for the Federal Circuit upheld a lower court decision, 7-4, ruling that Trump did not have the authority to impose the tariffs. The court said, “The core Congressional power to impose taxes such as tariffs is vested exclusively in the legislative branch by the Constitution. Tariffs are a core Congressional power.”
During Supreme Court oral arguments on Nov. 5, most justices appeared skeptical of the administration’s claim that the president had the authority to impose the tariffs. The court has expedited the appeal, but the timing and outcome remain uncertain.
Costco’s lawsuit emphasizes that even if the tariffs are later deemed unlawful, importers are not automatically guaranteed refunds without a separate judicial ruling. “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 filing said.
White House spokesperson Kush Desai said the suit “highlights” the economic consequences of potentially invalidating the tariffs and expressed hope for a “speedy and proper resolution” from the Supreme Court. The administration has warned that refunding hundreds of millions of dollars in tariffs could have major financial impacts if the court rules against Trump’s authority under IEEPA.