S.D. Codified Laws § 51A-6A-58
After first applying for and obtaining the approval of the director, one or more trust service offices may be established and operated by a trust company incorporated under the laws of this state or by an out-of-state trust institution, if and to the extent that the state, territory, or district in which the out-of-state trust institution is chartered or licensed to engage in a trust company business grants authority for a trust company organized and doing business under the laws of this state to establish an office in that state, territory, or district. An application to establish and operate a trust service office or to relocate an existing trust service office shall be submitted and approved in the manner set forth in § 51A-6A-4.
A trust company may establish a trust service office in another state, territory, or district and may conduct any activities at that office that are permissible for a trust company under the laws of that state, territory, or district subject to the laws of this state and subject to the rules, orders, or declaratory rules of the commission or the director.
The provisions of this section do not apply to a private trust company unless the governing board decides to establish a trust service office in another state, territory, or district.
SDCL 51A-6A-58