A federal judge appeared likely to expand litigation over refunds for President Donald Trump’s sweeping tariffs by granting a class-action certification, even as the administration has refunded roughly 60% of the $166 billion in unlawful duties.

Judge Richard Eaton, an appointee of former President Bill Clinton, heard arguments from both the Department of Justice and lawyers for the coalition of businesses made before the U.S. Court of International Trade, roughly six months after the Supreme Court struck down Trump’s “Liberation Day” tariffs. Eaton opened the hearing by commending the administration’s quick work in setting up a system to process refunds, the Consolidated Administration and Processing of Entries program, following the Supreme Court’s February ruling, but also expressed concern that “tens of thousands of importers” could still be denied refunds they are owed.