Mont. Code § 25-10-601
When the plaintiff in an action resides out of this state or is a foreign corporation, security for the costs and charges which may be awarded against such plaintiff may be required by the defendant. When required, all proceedings in the action must be stayed until an undertaking, executed by two or more persons, is filed with the clerk to the effect that they will pay such costs and charges as may be awarded against the plaintiff by judgment or in the progress of the action, not exceeding $300. A new or an additional undertaking may be ordered by the court or judge upon proof that the original undertaking is insufficient security and proceedings in the action stayed until such new or additional undertaking is executed and filed.
§ 25-10-601, MCA