India, Dec. 3 -- Costco Wholesale Corp. has formally joined a wave of lawsuits against the Trump administration's sweeping tariff orders, becoming the largest retailer yet to take legal action, CNBC reported.

The company filed in the U.S. Court of International Trade on November 28, 2025, seeking a full refund of duties it paid under tariffs imposed using the International Emergency Economic Powers Act (IEEPA).

Costco argued that its request for more time to finalise tariff calculations needed to preserve refund eligibility was denied by customs authorities. The company also stressed that IEEPA does not explicitly grant the President the power to impose tariffs.

It's a huge win for many small businesses and state-led groups, which have...