The "Tariff Refund Act of 2026" aims to rectify the unlawful collection of duties under the International Emergency Economic Powers Act (IEEPA), following a Supreme Court ruling. It establishes a clear mandate for the Commissioner of U.S. Customs and Border Protection (CBP) to refund, with interest, all such duties paid on covered articles. Specifically, the bill requires CBP to process these refunds within 180 days of the Act's enactment, even necessitating the reliquidation of previously settled entries. A significant provision is the directive for CBP to prioritize refunds for small business concerns and to collaborate with the Small Business Administration (SBA) for outreach, ensuring these businesses are informed about the refund process and required documentation. Furthermore, the bill includes a sense of Congress encouraging businesses that passed on these unlawful duty costs to their customers to also pass on the resulting refunds. To ensure transparency and accountability, the Commissioner must submit regular reports to Congress every 30 days until all refunds are completed, detailing the number and amount of refunds issued, with a breakdown for small businesses, and an estimated completion timeline. The bill also requires CBP to issue guidance on how to handle drawback claims related to these specific duties.