S.D. Codified Laws § 55-2-1
Current with legislation signed by the governor on or before 3/6/2024
In all matters connected with his trust a trustee is bound to act in the highest good faith toward his beneficiary and may not obtain any advantage therein over the latter by the slightest misrepresentation, concealment, threat, or adverse pressure of any kind.
SDCL 55-2-1