Mont. Code § 27-18-410
In addition to the method prescribed in 27-18-409 for attaching stock or shares or interest in the stock of any corporation or company, if the president or other head of the corporation or company or the secretary, cashier, or other managing agent of the corporation or company does not live in or cannot be found in Montana and an affidavit is filed in the office of the clerk of the court in which the action is pending setting forth that the officer or agent does not live in or cannot be found in Montana, the clerk shall make an order directing the writ to be served upon the secretary of state of Montana or, in the secretary of state's absence, upon the deputy secretary of state. When the order has been made, the writ of attachment must be served upon the secretary of state or deputy secretary of state by leaving with the secretary or the deputy a copy of the writ and a notice that the stock or shares or interest in the stock or shares of the corporation or company belonging to the defendant is attached in pursuance of the writ.
§ 27-18-410, MCA