Mont. Code Ann. § 32-1-508

The charters and the corporate existence of banks shall cease automatically and become nonexistent upon the completion of liquidation of the affairs of said bank, whether accomplished voluntarily or through legal process. For the purposes of this section, a bank's affairs shall be considered liquidated and completed when all of its property of every kind has been sold or applied toward the payment of its obligations and the corporation is left without property in existence or in reasonable expectancy.