(1) Domestic international sales corporations (DISCs) , as defined in sections 991 through 994 of the IRC, and foreign sales corporations, as defined in sections 921 through 927 of the IRC, are included in a water's-edge return. DISCs are specifically taxable not withstanding the general exempt language of 15-31-102 , MCA.

(2) Foreign corporations, if over 50% of the voting stock is owned directly or indirectly by a member of the includable group and if more than 20% of the average of its payroll and property is assignable to a location inside the United States, are included in a water's-edge return. For purposes of computing this average, the payroll factor provided for by 15-31-308 , MCA, and the property factor as provided for by 15-31-306 , MCA, shall be added together and divided by two, or by one if the denominator of either the property of payroll factor is zero.

(3) A corporation that is in a unitary relationship with the taxpayer and that is incorporated in a tax haven are included in a water's-edge return.