(1) The following must file an individual income tax or fiduciary return:

(a) Every resident who is a single person, and every resident who is a married person who does not elect or, as provided in ARM 42.15.321, is not allowed to elect, to file a joint return with a spouse, must file a return if the person's gross income from all sources for the taxable year is more than $1,500, adjusted as provided in (3) , plus the value of the exemptions the person is entitled to for age 65 or for blindness.

(b) Married persons, both of whom are residents, not filing separate returns must file a joint return if their combined gross income for the taxable year from all sources exceeds $3,000, adjusted as provided in (3) , plus the value of the exemptions they are entitled to for age 65 or blindness.

(c) Every nonresident who is a single person, and every nonresident who is a married person who does not elect or, as provided in ARM 42.15.321, is not allowed to elect, to file a joint return with a spouse, must file a return if the person's gross income from all sources is more than $1,500, adjusted as provided in (3) , plus the value of the exemptions the person is entitled to for age 65 or blindness, and they have any Montana source income.

(d) Married persons, both of whom are full-year nonresidents, not filing separate returns, must file a joint return if their combined gross income for the taxable year from all sources exceeds $3,000, adjusted as provided in (3) , plus the value of the exemptions they are entitled to for age 65 or blindness, and either or both of them have any Montana source income.

(e) The estate of a decedent who was a resident must file a return if its gross income for the year from all sources exceeds its exemption allowance.

(f) The estate of a decedent who was a nonresident must file a return if its gross income from all sources exceeds its exemption allowance, and the estate has any Montana source income.

(g) A nonbusiness trust which is not a grantor trust and is subject to the Montana Trust Code, Title 72, chapter 33, MCA, must file a return if its gross income for the year from all sources exceeds its exemption allowance.

(h) A business trust, including an REIT, is treated as a C corporation taxable under Title 15, chapter 31, MCA. See chapters 23 and 24 of Title 42, Administrative Rules OF MONTANA, for the corporation license tax rules.

(2) A nonresident's distributive share of a pass-through entity's Montana source income is included in determining a nonresident's obligation to file a Montana individual income tax return. A nonresident whose only Montana source income for the tax year is from one or more partnerships or S corporations, each of which has elected to file a composite return and pay a composite tax on behalf of consenting participants, is not required to file an individual income tax return. A nonresident who has Montana source income from a partnership or S corporation who does not elect to file a composite return or who has any other Montana source income (for example, wages from employment in Montana or rental income from property located in Montana), is required to file a Montana individual income tax return if the gross income from all sources, adjusted as provided in this rule, exceeds the applicable limit.

(3) By November 1 of each year the department will multiply the minimum amount of gross income necessitating the filing of a return by the inflation figure for the taxable year.