S.D. Codified Laws § 54-3A-11 (2026)
If the buyer has not paid an installment on an installment sales contract on or before the tenth day after its due date, as originally scheduled or as deferred, the creditor, if he chooses to impose a penalty for the delinquency, shall before the due date of the next scheduled installment, mail or deliver to the buyer at his last known address a written notice informing the buyer:
Source: SL 1974, ch 305 , § 8; SL 1975, ch 299 , § 3; SL 1990, ch 30 , § 13.