S.D. Codified Laws § 58-26-81
If in any contract year the gross premium charged by any company on any policy or contract is less than the valuation net premium for the policy or contract calculated by the method used in calculating the reserve thereon but using the minimum valuation standards of mortality and rate of interest, the minimum reserve required for the policy or contract is the greater of either the reserve calculated according to the mortality table, rate of interest, and method actually used for the policy or contract, or the reserve calculated by the method actually used for the policy or contract but using the minimum valuation standards of mortality and rate of interest and replacing the valuation net premium by the actual gross premium in each contract year for which the valuation net premium exceeds the actual gross premium. The minimum valuation standards of mortality and rate of interest referred to in this section and § 58-26-82 are those standards stated in §§ 58-26-56 to 58-26-63, inclusive, and §§ 58-26-71 to 58-26-74, inclusive.
SDCL 58-26-81