S.D. Codified Laws § 3-13A-4
The program shall be under the authority of the board. The board shall be held to the standard of conduct of a fiduciary and shall carry out its functions solely in the interest of the participants and benefit recipients and for the exclusive purpose of providing benefits and defraying reasonable expenses incurred in performing such duties as required by law. The board may promulgate rules necessary to establish uniform procedures for the administration of the program and to insure uniformity of application of the provisions of §§ 3-13A-1 to 3-13A-25, inclusive. Rules may be promulgated in regard to membership, contributions and the collection thereof, fees for administration of the program, and procedures for application for benefits and payment of benefits. The rules shall be promulgated pursuant to chapter 1-26 and shall be in accordance with the provisions of §§ 3-13A-1 to 3-13A-25, inclusive.
SDCL 3-13A-4