S.D. Codified Laws § 47-11G-9

A corporation formed pursuant to this chapter may adopt a pension profit-sharing, a health and accident, an insurance, or a welfare plan for all or some of its employees, including lay employees, if the plan does not require or result in the sharing of specific or identifiable fees with lay employees, and if any payments made to lay employees or into any such plan on behalf of lay employees are based on their compensation, their length of service, or both, rather than the amount of fees or income received.