S.D. Codified Laws § 55-2-8
Current with legislation signed by the governor on or before 3/6/2024
All transactions between a trustee and his beneficiary during the existence of the trust or while the influence acquired by the trustee remains, by which he obtains any advantage from his beneficiary, are presumed to be entered into by the latter without sufficient consideration and under undue influence.
SDCL 55-2-8