S.D. Codified Laws § 55-5-7
No specific investment or course of action is, taken alone, prudent or imprudent. The trustee may invest in every kind of property and type of investment, subject to this chapter. The prudent investor rule is a test of conduct and not of resulting performance. The prudent investor rule may be expanded, restricted, eliminated, or otherwise altered by the terms of the trust instrument or court order. Unless expanded, restricted, eliminated, or otherwise altered by the terms of the trust instrument or a court order, the trustee's investment decisions and actions shall be judged in terms of the trustee's reasonable judgment regarding the anticipated effect on the trust portfolio as a whole under the facts and circumstances prevailing at the time of the decision or action. No trustee is liable to a beneficiary to the extent that the trustee acted in reliance on the provisions of the trust instrument or court order.
SDCL 55-5-7