Montana Title 35. Corporations, Partnerships, and Associations § 35-2-132. Ultra vires

(1) Except as provided in subsection (2), the validity of corporate action may not be challenged on the ground that the corporation lacks or lacked power to act.

(2) A corporation's power to act may be challenged in a proceeding against the corporation to enjoin an act when a third party has not acquired rights. The proceeding may be brought by the attorney general, by a director, or by a member or members in a derivative proceeding.