S.D. Codified Laws § 61-5-56

If, not later than three years after the date on which any contributions or interest thereon have been paid, an employer who has paid the contributions or interest thereon makes application for adjustment thereof in connection with subsequent contribution payments, or for a refund thereof because the adjustment cannot be made, and the department determines that the contributions or interest, or any portion thereof, was erroneously collected, the department shall allow the employer to make an adjustment thereof, without interest, in connection with subsequent contribution payments by the employer. However, if the adjustment cannot be made, the department shall refund the amount, less any benefits which have been paid from the amount, without interest from the fund. For like cause and within the same period, adjustment or refund may be so made on the department's own initiative.