A proposed class action lawsuit filed against Costco accuses the retail giant of retaining financial benefits from federal tariffs that were recently struck down by the U.S. Supreme Court.

The lawsuit, as reported by KING 5 News, was filed in the U.S. District Court for the Western District of Washington. It alleges that the company raised prices to offset the cost of import duties but has failed to commit to refunding those same customers now that the government is expected to return the funds.

The dispute stems from tariffs imposed by President Donald Trump’s administration in February 2025 under the International Emergency Economic Powers Act. Seven named plaintiffs from Washington, Ohio, California and Pennsylvania claim they were charged higher prices for imported goods as the retailer passed the tax burden directly to shoppers.

On February 20, the Supreme Court ruled these specific tariffs were unlawful, paving the way for businesses to reclaim billions of dollars in paid duties.

Lawyers for the plaintiffs argue that Costco now stands to collect the same money twice — once from the customers who paid inflated prices at the checkout and a second time via government refunds.

The complaint describes this as a form of unjust enrichment, noting that while Costco has actively pursued its own litigation to recover the duties, it has not promised to redistribute those specific refunds to the customers who originally bore the cost.

Chief Executive Ron Vachris previously told analysts that any potential tariff refunds would be used to provide lower prices and better value for customers in the future. However, the lawsuit contends this approach would only benefit a general group of future shoppers rather than the specific people who were financially disadvantaged during the tariff period between February 2025 and February 2026.

Evidence cited in the filing includes Costco’s own public acknowledgments during earnings calls that tariffs were influencing its pricing strategies.

The plaintiffs also point to the fact that the retailer reduced prices on certain items once the tariff pressure had eased, which they claim demonstrates a direct link between the federal duties and the higher costs previously paid by members.

If successful, the lawsuit would cover any shoppers across the United States who purchased goods subject to these tariffs at Costco during the yearlong period.

Costco has not yet issued a formal comment on the pending litigation.

The Independent has contacted Costco for comment.