The United States Supreme Court has struck down President Donald Trump's sweeping tariffs, saying the International Emergency Economic Powers Act did not grant him the power to impose levies. So far, the duties are estimated to have brought in more than US$175 billion. Legally, those funds may have to be returned, but the process is far from straightforward. Heng Koon How, head of markets strategy at UOB, discusses on CNA's Asia First why refunds could take years and what hurdles lie ahead.