S.D. Codified Laws § 58-41-54
A health maintenance organization may, subject to the limitations of subdivision 58-41-17(5) and of § 58-41-19, contract with insurance companies and nonprofit health service plan corporations for insurance, indemnity, or reimbursement of its cost of providing health care services for enrollees or against the risks incurred by the health maintenance organization and may contract with insurance companies and nonprofit health service plan corporations to insure or cover the enrollees' costs and expenses in the health maintenance organization, including the customary prepayment amount and any copayment obligations. If contracts are made with insurance companies or nonprofit health service plan corporations, such companies or corporations must be authorized to transact business in this state.
SDCL 58-41-54