More than 70 companies, including Costco, the world’s largest warehouse-style retailer, have filed lawsuits seeking assurances of tariff refunds against the Trump administration. Even if the U.S. Supreme Court rules that President Trump’s imposition of reciprocal tariffs is unlawful, they are moving to set up safeguards in advance because the Trump administration is unlikely to automatically refund the duties.

On the 28th of last month (local time), Costco filed a tariff refund lawsuit against the Trump administration in the U.S. Court of International Trade. In its complaint, Costco stated that “even if the Supreme Court finds that the reciprocal-tariff executive order under the International Emergency Economic Powers Act (IEEPA) is unlawful, refunds of illegally collected duties are not guaranteed without a separate court order,” and asked the court to initiate a refund process.

Forbes reported that, as of now, more than 70 companies have filed tariff refund suits like Costco, including nine Japan-affiliated firms such as Toyota Tsusho and Sumitomo Chemical; cosmetics company Revlon; motorcycle maker Kawasaki Motors; aluminum producer Alcoa; and canned-food company Bumble.

Mark Busch, a trade-law scholar at Georgetown University, said, “Until now, tariff litigation has mostly been led by small and midsize companies. This is the first time major corporations have openly pushed back.” Forbes also pointed out about the participation of large companies such as Costco that it “signals a new phase in the legal fight over tariffs.”

In April, Amazon considered listing tariff costs separately on price tags, but drew President Trump’s public ire and saw its share price plunge. Since then, large companies have been reluctant to criticize tariff policy openly.

Despite the risk of becoming targets of the Trump administration, even big corporations have begun rushing to file suits because duties already paid will be finalized within the next few weeks. Under U.S. customs law, Customs and Border Protection (CBP) under the Department of Homeland Security ‘liquidates’ duties after a certain period following a company’s import entry. This ‘liquidation’ is the official procedure that sets the duty amount.

Once duties are finalized, even if the Supreme Court later rules the tariffs unlawful, the room to challenge them or seek refunds is severely limited. Costco and others said in their complaint that they “asked the Trump administration to extend the duty-finalization schedule, but CBP refused,” and requested that “the court protect their right to obtain refunds safely.”

Professor Busch told CNN, “Companies seem to have no faith that, even if an illegality ruling comes down on the tariffs, the Supreme Court and the administration will set up a systematic refund process,” adding that “more firms are likely to join the litigation like Costco.”

Because the Supreme Court already held oral arguments in November, it can issue a ruling at any time. Typically the Court takes several months after argument to decide, but given the unusually expedited handling of this case, some expect a ruling as early as this month.

Forbes noted that “it is true the justices expressed skepticism about the tariffs during argument, but they also voiced concern that refunds could cause major disruption,” adding that “a ruling that voids the tariff policy but disallows retroactive application cannot be ruled out.”