The nation’s biggest warehouse club chain is among dozens of companies to file lawsuits in a US trade court since late October challenging President Donald Trump’s use of an economic emergency powers law to impose the levies, according to court records. It’s one of the biggest corporate players to jump into a fight largely driven this year by small businesses and Democratic state officials.

The Supreme Court heard arguments on Trump’s tariffs on Nov. 5. The justices put the fight on a fast-tracked schedule but didn’t say when they intend to rule. In the meantime, businesses of all sizes have brought cases pressing similar legal claims with the goal of avoiding uncertainty about their eligibility for refunds if the court rules against Trump.

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Costco’s lawyers wrote that the complaint, filed on Nov. 28 in the US Court of International Trade, was prompted due to the uncertainty that refunds will be guaranteed for all businesses that have been paying duties if the Supreme Court declares the tariffs unlawful.

The lawsuit doesn’t specify how much Trump’s tariffs have cost the company to date.

Costco argues that it needs a court intervention immediately because Customs and Border Protection denied its request to extend the schedule for finalizing tariff determinations under Trump’s use of the International Emergency Economic Powers Act. The company says that could jeopardize its ability to seek full refunds in the future. 

Costco didn’t immediately respond to requests for comment on Monday.

White House spokesperson Kush Desai said in a statement that, “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.”

Skeptical Justices

During arguments before the Supreme Court last month, key justices appeared skeptical of Trump’s tariffs, which have generated tens of billions of dollars a month. Lower federal courts ruled against the administration in a handful of lawsuits filed early on, but judges have allowed the government to enforce the tariffs until the Supreme Court issues its decision.

Other household names to bring tariff lawsuits in recent weeks include cosmetics giant Revlon Consumer Products Corp. and motorcycle maker Kawasaki Motors Manufacturing Corp.

The expansive, fast-changing tariff policies have disrupted the retail sector this year, threatening to raise prices of goods and hamper the purchasing power of US consumers who are already cautious following years of inflation.

The impact has been more muted than expected due to exemptions and changes in rates after negotiations, though some items such as electronics and apparel are more expensive compared to a year ago. While retailers have warned that they continue to see higher costs, many big operators have not pursued lawsuits like Costco — making it an outlier. 

Read More: What’s at Stake as Trump’s Tariffs Face Supreme Court

Costco has said it’s working to mitigate tariffs, which primarily affect its non-food items. It has rerouted some products to non-US markets, ordered more inventory early to get ahead of the levies and purchased from fewer suppliers by consolidating buying. When items get too expensive, it’s changing merchandising altogether.

“We’re doing everything we can,” Chief Financial Officer Gary Millerchip said in an interview with Bloomberg News earlier this year. “Whether that’s working with the suppliers to find efficiencies to offset the impact of tariffs, or whether it’s sourcing with them often to different countries.” 

For example, Costco said in May that it kept steady prices of pineapples and bananas imported from Central and South America because they are important items to customers. At the same time, it increased prices of flowers sourced from the region because they are less of a necessity to shoppers. 

The club chain said its big size and limited assortment — its stores carry a couple thousand items versus over 100,000 for some big-box retailers — give it a leg-up when navigating tariffs. Still, it’s difficult to predict what will happen to prices, company executives said.

The case is Costco Wholesale Corp. v. Customs and Border Protection, 1:25-cv-316, US Court of International Trade.