Costco Sues Trump Administration Seeking Full Tariff Refunds. Retail giant Costco has filed a lawsuit against the U.S. government, demanding a full refund of import tariffs if the Supreme Court ultimately rules that President Donald Trump lacked the authority to impose them without Congress - According to BBC. The company is urging the Court of International Trade to declare Trump’s “emergency” tariffs unlawful, despite his claim that the International Emergency Economic Powers Act allowed him to act unilaterally. Lower courts have already ruled that Trump overstepped his powers, and the case is now before the Supreme Court. Costco says it has suffered financially under the tariffs and fears it won’t get its money back unless it pursues its own legal action. While the retailer didn’t disclose how much it hopes to recover, government data shows importers have paid roughly $90 billion in IEEPA-related tariffs. Costco filed its suit ahead of a December 15, 2025 deadline, after which recovering those funds would be far more difficult. The Trump administration maintains the tariffs were legal and warns that overturning them could cost the U.S. treasury billions and weaken the country’s negotiating leverage.