S.D. Codified Laws § 10-44-16

All taxes and installments not paid when due shall be paid together with a penalty assessment on the unpaid balance at the rate of one and one-half percent per month, or fraction thereof. The Division of Insurance may refund any penalty or interest paid in error. Upon written request by a receiver, the director of the Division of Insurance may extend the time for payment of the tax and may waive any penalty assessment.