Revenue and taxation; interest rate computations; state tax liabilities; effective date.

HB 2730 amends Oklahoma's tax interest and penalty rules for state tax liabilities. It changes the interest rate calculation for delinquent taxes to use Wall Street Prime plus 3 percentage points (previously fixed rates), adjusts penalty timelines (15 days for sales/tax delinquencies vs. 30 days for others), and modifies refund interest deadlines (30 days for electronic filings, 90 days for paper after 2010). These changes directly affect Oklahoma taxpayers who owe state taxes, including those with late payments, underpayments, or delayed refunds. The bill takes effect November 1, 2025, applying to all delinquent accounts existing or occurring after that date.