Businesses big and small have started receiving tariff refunds after the US Supreme Court ruled that President Donald Trump lacked the constitutional authority to impose higher import taxes on goods from nearly every other country.

The process could grind to a halt, however, after the Trump administration said Friday that it intended to appeal a federal judge's order to allow all companies that paid the invalidated duties to seek refunds, not just the ones that filed lawsuits.

Until the Department of Justice informed the judge of its planned appeal, the refund system overseen by US Customs and Border Protection had been working fairly smoothly. Refunds reached the bank accounts of the first successful applicants on May 12, about three weeks after importers and their customs brokers could start submitting claims through an online system, according to CBP.