S.D. Codified Laws § 51A-6A-13
The business of any trust company shall be managed and controlled by its governing board and includes the authority to provide for bonus payments, in addition to ordinary compensation, for any of its officers and employees. The governing board of a private trust company shall consist of not less than three nor more than twelve members, all of whom shall be elected by the owners of the trust company at any regular annual meeting, with terms not to exceed three years. The governing board of a public trust company shall consist of not less than five nor more than twelve members, all of whom shall be elected by the owners of the trust company at any regular meeting held during each calendar year. If the number of board members elected is less than twelve, the number of board members may be increased so long as the total number does not exceed twelve. If the number is increased, the first additional board members may be elected at a special meeting of the owners. The board members shall be elected and any vacancies filled in the manner as provided in the provisions regarding general corporations or limited liability companies, as applicable. At all times one of the directors shall be a resident of this state and at least one-half of the directors shall be citizens of the United States. Any board member of any trust company who becomes indebted to the trust company on any judgment forfeits the position of board member, and the vacancy shall be filled as provided by law.
SDCL 51A-6A-13