SDCL § 47-1A-627.1: Purposes for which restriction on transfer of shares and registration of transfer of shares authorized--Validity and enforceability of restriction.

A restriction on the transfer or registration of transfer of shares is valid and enforceable against the holder or a transferee of the holder if the restriction is authorized by this section and its existence is noted conspicuously on the front or back of the certificate or is contained in the information statement required by § 47-1A-626. Unless so noted, a restriction is not enforceable against a person without knowledge of the restriction. A restriction on the transfer or registration of transfer of shares is authorized:

(1) To maintain the corporation's status when it is dependent on the number or identity of its shareholders;

(2) To preserve exemptions under federal or state securities law;

(3) For any other reasonable purpose.