A lawsuit filed by Costco to preserve its right to tariff refunds—should the US Supreme Court strike down roughly half of the Trump-era duties—is expected to trigger a wave of similar actions by other companies.
Under current rules, companies have 180 days after imported goods are “liquidated” to challenge the assessed duties and request refunds from US Customs. Duties are generally paid when goods enter the country, but the final tariff amount is not determined until liquidation, which typically occurs within 314 days of entry.
Costco is among a growing group of companies, including Kawasaki Motors and Bumble Bee Foods, that are filing precautionary suits in the US Court of International Trade to avoid missing refund deadlines. Costco’s November 28 filing did not specify a refund amount.
On November 5, the US Supreme Court heard arguments on whether President Trump had authority under the International Emergency Economic Powers Act to impose tariffs via Truth Social posts or executive orders, or whether a more formal process is required.
The case implicates reciprocal tariffs of 10% to 50% on imports from nearly every country, along with special tariffs on Canada, Mexico, and China tied to fentanyl-related enforcement. While the 50% tariffs on Brazil (in response to the Bolsonaro prosecution) and India (related to Russian oil sales) are not directly before the court, the ruling could affect them as well.
The US currently collects roughly $30 billion per month in tariffs, about half of which is potentially refundable.
If the court invalidates the tariffs, immediate refunds are unlikely. The justices may instead remand the issue to lower courts to determine appropriate remedies. The US Court of International Trade and its appellate court may establish a new administrative refund process or rely on existing channels. They could also accept the government’s argument that retroactive refunds of billions already collected would have severe economic consequences, and thus limit relief to future collections only.
Importers should promptly identify the liquidation dates for all entries. If no entries are close to liquidation, it may be advantageous to wait and see whether the Supreme Court issues a decision soon. The ruling could come anytime from later this month through next summer, when most major decisions are announced.