S.D. Codified Laws § 62-6-4

All books, records, and payrolls of employers coming under this title, showing and in any way referring to the amount of wage expenditure of such employer, shall always be open for inspection by the department or any of its representatives presenting a certificate of authority from the department, for the purpose of ascertaining the correctness of the wage expenditure, the number of employees, and such other information as may be necessary for the uses and purposes of the department in the administration of the provisions of this title.