A trustee, whether he receives any compensation or not, must use at least ordinary care and diligence in the execution of his trust. Source: SDC 1939, § 59.0205.
Degree of care and diligence used in execution of trusts
SDCL § 55-3-10 — under EXPRESS TRUSTS FOR THIRD-PARTY BENEFICIARIES.
SDCL § 55-3-10