• Costco is suing the Trump administration seeking a full refund of tariffs.
• The lawsuit claims tariffs imposed under Trump's orders are unlawful.
• Dozens of companies are joining Costco in seeking refunds as the Supreme Court deliberates.
• The case hinges on the legality of tariffs imposed under the International Emergency Economic Powers Act.

Costco has filed a lawsuit against the Trump administration, aiming for a full refund of the tariffs it paid on imports if the Supreme Court rules these tariffs illegal. The retailer, a significant importer, contends the administration has overstepped its authority under the International Emergency Economic Powers Act (IEEPA). This lawsuit comes as the Supreme Court reviews the legality of Trump's extensive tariffs on various imports, with lower courts previously determining that these tariffs were imposed unlawfully, according to Los Angeles Times and NPR.

Costco is the latest major company to join dozens of other businesses seeking refunds if the Supreme Court finds Trump's tariffs illegal. These include Revlon and motorcycle manufacturer Kawasaki among others. “This is the first time we’re seeing big companies take their heads out of the sand publicly,” remarked Marc Busch, a trade law expert, underscoring the significance of Costco's legal challenge, according to The Hill and NPR.

In its filing, Costco emphasized the unpredictability of receiving refunds without a court ruling, indicating the necessity of their own separate legal action. The company, represented by law firm Crowell & Moring, which is handling numerous similar lawsuits, is concerned that even a favorable Supreme Court ruling may not guarantee full recovery of the tariffs paid, as the retailers cope with rising costs of imported goods exacerbated by these tariffs, as noted by Los Angeles Times, The Hill, and NPR.