Revenue and taxation; interest on delinquent taxes; interest on refunds; effective date.

HB 1204 modifies Oklahoma's tax interest and penalty rules. It sets interest on delinquent taxes at the prime rate plus 1.25% per month (published annually in *The Wall Street Journal*), and adjusts penalties: 10% after 15 days for sales/tourism taxes, or 30 days for other taxes. For refunds, it requires the Tax Commission to pay interest starting 90 days after filing (for electronic returns) or 150 days (for paper returns), effective for tax years 2025 and later. The bill directly affects all Oklahoma taxpayers who owe taxes or are due refunds.