Mont. Code Ann. § 35-2-820

35-2-820 . Authority to transact business required. (1) A foreign corporation may not transact business in this state until it obtains a certificate of authority from the secretary of state.

(2) The following activities, among others, do not constitute transacting business within the meaning of subsection (1):

(a) maintaining, defending, or settling any proceeding;

(b) holding meetings of the board of directors or members or carrying on other activities concerning internal corporate affairs;

(c) maintaining bank accounts;

(d) maintaining offices or agencies for the transfer, exchange, and registration of memberships or securities or maintaining trustees or depositaries with respect to those securities;

(e) selling through independent contractors;

(f) soliciting or obtaining orders, whether by mail or through employees or agents or otherwise, if the orders require acceptance outside this state before they become contracts;

(g) creating or acquiring indebtedness, mortgages, and security interests in real or personal property;

(h) securing or collecting debts or enforcing mortgages and security interests in property securing the debts;

(i) owning real or personal property:

(i) that is acquired incident to activities described in subsection (2)(h) if the property is disposed of within 5 years after the date of acquisition; or

(ii) that does not produce income or is not used in the performance of a corporate function;

(j) conducting an isolated transaction that is completed within 30 days and that is not a transaction in the course of repeated transactions of a similar nature; or

(k) transacting business in interstate commerce.

(3) The list of activities in subsection (2) is not exhaustive.