Costco is reportedly joining a coalition of companies preparing to sue for duty refunds if the Supreme Court invalidates Trump-era tariffs imposed under the International Emergency Economic Powers Act (IEEPA). This legal action could lead to significant financial impacts for retailers and import-heavy sectors, potentially resulting in one-time cash inflows if refunds are granted. A Supreme Court decision limiting the use of emergency tariff powers might shift the focus to Section 301 and 232 authorities, which necessitate formal investigations. This could create a temporary enforcement gap, affecting various industries. Steel and aluminum producers, in particular, may experience price pressures if Section 232 duties are suspended.