S.D. Codified Laws § 58-37A-20
For certificates issued before one year after January 1, 1991, the value of every paid-up nonforfeiture benefit and the amount of any cash surrender value, loan, or other option granted shall comply with the provisions of law applicable immediately before January 1, 1991.
For certificates issued on or after one year from January 1, 1991, every paid-up nonforfeiture benefit and the amount of any cash surrender value, loan, or other option granted may not be less than the corresponding amount based on the interest rate and mortality tables authorized by the laws of this state for the calculation of these benefits by life and health insurers issuing policies containing like benefits based upon such interest rate and mortality tables.
SDCL 58-37A-20