S.D. Codified Laws § 3-13C-13.3

The death and disability benefits provided by the system are limited by the incidental benefit rule set forth in § 401(a)(9)(G) of the Internal Revenue Code and Treasury Regulation § 1.401-1(b)(1)(i). As a result, the total death or disability benefits payable may not exceed twenty-five percent of the cost for all of the member's benefits received from the system.