S.D. Codified Laws § 58-15-26.2
Interest payable pursuant to § 58-15-26.1 shall be computed from the date of death of the insured until the date of payment and shall be at the rate of four percent per annum or not less than the current rate of interest on death proceeds left on deposit with the insurer under an interest settlement option, whichever rate is greater. For any private placement policy, the interest shall be computed commencing the latter of sixty days succeeding the date of death of the insured or the date proof of death has been received by the insurer in good order until the date of payment. In any private placement policy, the obligation of the insurer to pay interest on that portion of the policy attributable to separate account assets may only be computed as and when such assets are, by their respective terms, either converted to cash or otherwise dispersible by the insurer.
SDCL 58-15-26.2