SDCL § 57A-1-310: Subordinated obligations.

An obligation may be issued as subordinated to performance of another obligation of the person obligated, or a creditor may subordinate its right to performance of an obligation by agreement with either the person obligated or another creditor of the person obligated. Subordination does not create a security interest as against either the common debtor or a subordinated creditor.

Source: SL 2008, ch 259, § 24.