(1) Under 15-31-301 and 15-1-601, Article IV(2) , MCA, the taxpayer is subject to the allocation and apportionment provisions of Title 15, chapter 31, part 3, MCA, if it has income from business activity that is taxable both within and without this state.   A taxpayer's income from business activity is taxable without this state if such taxpayer, by reason of such business activity (i.e., the transactions and activity occurring in the regular course of a particular trade or business) , is taxable in another state within the meaning of 15-31-303, MCA.

(2) A taxpayer is not taxable in another state with respect to a particular trade or business merely because the taxpayer conducts activities in such other state pertaining to the production of non-business income or business activities relating to a separate trade or business.