S.D. Codified Laws § 22-40-20
Following the discovery by or notification to an information holder of a breach of system security an information holder shall disclose in accordance with § 22-40-22 the breach of system security to any resident of this state whose personal or protected information was, or is reasonably believed to have been, acquired by an unauthorized person. A disclosure under this section shall be made not later than sixty days from the discovery or notification of the breach of system security, unless a longer period of time is required due to the legitimate needs of law enforcement as provided under § 22-40-21. An information holder is not required to make a disclosure under this section if, following an appropriate investigation and notice to the attorney general, the information holder reasonably determines that the breach will not likely result in harm to the affected person. The information holder shall document the determination under this section in writing and maintain the documentation for not less than three years.
Any information holder that experiences a breach of system security under this section shall disclose to the attorney general by mail or electronic mail any breach of system security that exceeds two hundred fifty residents of this state.
SDCL 22-40-20