S.D. Codified Laws § 10-45-20.3
For the purposes of this chapter, a controlled group consists of any corporations or other entities eligible to file a consolidated federal income tax return under the Internal Revenue Code as in effect on January 1, 2002, or entitled to only a single surtax exemption for federal corporate income tax purposes under the Internal Revenue Code as in effect on January 1, 2002, and includes a controlled group of corporations as defined at 26 U.S.C. § 1563 as in effect on January 1, 2002. A controlled group also consists of any subchapter S corporation, limited liability company, limited liability partnership, general partnership, or limited partnership with at least eighty percent common ownership as if the entity was converted to or taxed as a subchapter C corporation under the Internal Revenue Code as in effect on January 1, 2002.
SDCL 10-45-20.3