Mont. Code § 61-4-406
In addition to the criminal and civil penalties provided in this part, any person who is injured in the person's business or property by any other person or corporation or association or partnership by reason of anything forbidden or declared to be unlawful by this part may sue for damages in any court having jurisdiction in the county where the defendant resides or is found or any agent resides or is found or where service may be obtained, without respect to the amount in controversy, and recover twice the amount of damages sustained and the costs of suit. Whenever it appears to the court before which any proceedings under this part may be pending that the ends of justice require that other parties must be brought before the court, the court may cause them to be made parties defendant and summoned, whether or not they reside in the county where the action is pending.
§ 61-4-406, MCA