S.D. Codified Laws § 51A-5-8
A bank or trust company organized and doing trust business under the laws of any state or territory of the United States of America, including the District of Columbia, other than South Dakota, and a national bank, duly authorized so to act, may be appointed and may serve in this state as trustee, whether of a corporation or personal trust, personal representative, guardian, conservator, or committee for an incompetent person, or in any other fiduciary capacity, whether the appointment is by will, deed, court order, or decree, or otherwise, when and to the extent that the state, territory, or district in which the bank or trust company is organized or has its principal place of business grants authority to serve in like fiduciary capacities to a bank or trust company organized and doing business under the laws of this state.
SDCL 51A-5-8