The gross income of individuals must be allocated and apportioned as follows:

1.     a.    Income from personal or professional services performed in this state by individuals must be assigned to this state regardless of the residence of the recipients of such income, except that income from such services performed within this state by an individual who resides and has the individual’s place of abode in another state to which place of abode the individual customarily returns at least once a month must be excluded from the individual’s income for the purposes of this chapter if such income is subject to an income tax imposed by the state in which the individual resides, provided that the state in which the individual resides allows a similar exclusion for income received from similar services performed in that state by residents of North Dakota.

b.    Notwithstanding any other provision of this chapter, the compensation received from services performed within this state by an individual, who performs services for a common carrier engaged in interstate transportation and who resides and has the individual’s place of abode to which the individual customarily returns at least once a month in another state, must be excluded from income to the extent that the income is subject to an income tax imposed by the state of the     individual’s residence; provided, that the state allows a similar exclusion of the compensation received by residents of North Dakota for similar services performed therein, or a credit against the tax imposed on the income of residents of this state that is substantially similar in effect. For purposes of this subdivision, the term an individual who performs services for a common carrier engaged in interstate transportation is limited to an individual who performs the services for a common carrier only during the course of making regular runs into North Dakota or from within North Dakota to outside North Dakota, or both, on the transportation system of the common carrier.

2.    Income received from personal or professional services performed by residents of this state, regardless of where such services are performed, and income received by residents of this state from intangible personal property must be assigned to this state.

3.    Income and gains received from tangible property not employed in the business and from tangible property employed in the business of the taxpayer, if such business consists principally of the holding of such property and collection of income and gains therefrom, must be assigned to this state without regard to the residence of the recipient if such property has a situs within this state.

4.    Income derived from business activity carried on by an individual as a sole proprietorship, or through a partnership, subchapter S corporation, or other passthrough entity, must be assigned to this state without regard to the residence of the individual if the business activity is conducted wholly within this state. Income derived from gaming activity carried on in this state by an individual must be assigned to this state without regard to the residence of the individual.

5.    Whenever business activity is carried on partly within and partly without this state by a nonresident of this state as a sole proprietorship, or through a partnership, subchapter S corporation, or other passthrough entity, the entire income therefrom must be allocated to this state and to other states, according to the provisions of chapter 57-38.1 but only according to the apportionment method provided under subsection 1 of section 57-38.1-09, providing for allocation and apportionment of income of corporations doing business within and without this state.

6.     a.    Income and gains received by a resident of this state from tangible property not employed in the business and from tangible property employed in the business of the taxpayer, if the business consists principally of the holding of the property and the collection of income and gains from the business, must be assigned to this state without regard to the situs of the property.

b.    Income derived from business activity carried on by residents of this state, whether the business activity is conducted as a sole proprietorship, or through a partnership, subchapter S corporation, or other passthrough entity, must be assigned to this state without regard to where the business activity is conducted, and the provisions of chapter 57-38.1 do not apply. If the taxpayer believes the operation of this subdivision with respect to the taxpayer’s income is unjust, the taxpayer may petition the tax commissioner who may allow use of another method of reporting income, including separate accounting.

7.    All other items of gross income must be assigned to the taxpayer’s domicile.

8.    The privileges granted nonresidents apply only when other states grant to the residents of North Dakota the same privilege.