S.D. Codified Laws § 47-1A-601

The articles of incorporation shall set forth any classes of shares and series of shares within a class, and the number of shares of each class and series, that the corporation is authorized to issue. If more than one class or series of shares is authorized, the articles of incorporation shall prescribe a distinguishing designation for each class or series and shall describe, prior to the issuance of shares of a class or series, the terms, including the preferences, rights, and limitations, of that class or series. Except to the extent varied as permitted by this section, all shares of a class or series shall have terms, including preferences, rights, and limitations, that are identical with those of other shares of the same class or series. Terms of shares may be made dependent upon facts objectively ascertainable outside the articles of incorporation in accordance with §§ 47-1A-120.1 to 47-1A-120.3 , inclusive. Any of the terms of shares may vary among holders of the same class or series so long as such variations are expressly set forth in the articles of incorporation.

Source: SL 2005, ch 239, § 53.