S.D. Codified Laws § 55-17-7
In addition to other transfers of property to a South Dakota special spousal trust, property is considered transferred to a South Dakota special spousal trust if the property is subject to a nonprobate transfer on death under an insurance policy, contract of employment, bond, mortgage, promissory note, certificated or uncertificated security, account agreement, custodial agreement, deposit agreement, compensation plan, pension plan, individual retirement plan, employee benefit plan, trust, conveyance, deed of gift, marital property agreement, or other written instrument of a similar nature and the South Dakota special spousal trust is designated as a beneficiary to receive the property under the transfer. The property is considered the surviving spouse's property that is not South Dakota special spousal property.
SDCL 55-17-7