Mont. Code § 35-16-211
If any stockholder or member of an existing cooperative or other corporation, association, society, or group of individuals declines to consent to the transfer or refuses to become a member of the new organization, the stockholder or member shall, within 30 days after receiving written notice of the transfer of assets to the new corporation or district, serve upon the officers of the newly created corporation or district and file in the district court of the county of its principal place of business a petition praying for the net value of the stockholder's or member's equity in the cooperative or other corporation, association, society, or group of individuals in its assets, determined and valued as of the date when the property was transferred by the directors or executive officers to the new corporation or district. Upon a failure to, within the time and in the manner specified in this section, file a claim for appraisal and settlement, it is barred.
§ 35-16-211, MCA