See rules 701-10.6 (421) and 701-10.2 (421) for failure to timely file a return or for failure to timely pay the tax. See rule 701-10.8 (421) for penalty exceptions. See rule 701-10.72 (452A) for interest on refunds.
Iowa Admin. Code r. 701-259.8
ARC 6508C, IAB 9/7/22, effective 10/12/22