(a) A shareholders' agreement authorized by this subchapter ceases to be effective when shares of the corporation are:
(1) listed on a national securities exchange; or
(2) regularly traded in a market maintained by one or more members of a national or affiliated securities association.
(b) If a corporation does not have a board of directors and an agreement of the shareholders of the corporation entered into under this subchapter ceases to be effective, a board of directors shall be instituted or reinstated to govern the corporation in the manner provided by Section 21.710(c).
(c) If a shareholders' agreement that ceases to be effective is contained in or referred to by the certificate of formation or bylaws of a corporation, the board of directors of the corporation may adopt an amendment to the certificate of formation or bylaws, without shareholder action, to delete the agreement and any references to the agreement.