S.D. Codified Laws § 3-13-102
Automatic enrollment--Contract
Automatic enrollment, pursuant to § 3-13-98 , is deemed a contract to participate, and to defer the amount specified in § 3-13-100 or revised by § 3-13-101 , or specified by the enrollee, until the automatic enrollee chooses to withdraw from the plan.
Source: SL 2025, ch 27, § 129.