Haw. Rev. Stat. § 235-5 – Allocation of income of persons not taxable upon entire income.

(a) This section applies to income not subject to part II of this chapter, including nonbusiness income and certain section 235-22 income.
(b) Income (including gains), also losses, from property owned in the State and from any other source in the State shall be determined by an allocation and separate accounting so far as practicable. Losses from property owned outside the State and from other sources outside the State shall not be deducted.
(c) Deductions connected with income taxable under this chapter shall be allowed, but deductions connected with income not taxable under this chapter shall not be allowed. Deductions from adjusted gross income that are not connected with particular property or income, such as medical expenses, shall be allowed only to the extent of the ratio of the adjusted gross income attributed to this State to the entire adjusted gross income computed without regard to source in the State.
Deductions by individual taxpayers from gross income for alimony and separate maintenance payments under section 215 of the Internal Revenue Code shall be allowed only to the extent of the ratio of gross income attributed to this State to the entire gross income computed without regard to source in this State; provided that as used in this sentence "gross income" means gross income as defined in the Internal Revenue Code, minus the deductions allowed by section 62 of the Internal Revenue Code, other than the deductions for alimony and separate maintenance payments under section 215 of the Internal Revenue Code.
Deductions by individual taxpayers from gross income for pension, profit-sharing, stock bonus plans, and other plans qualified under sections 401 to 409 of the Internal Revenue Code, as such sections are operative for the purposes of this chapter, shall be allowed only to the extent that such deductions are attributed to compensation earned in this State.
(d) The standard deduction as provided in section 235-2.4 and personal exemptions as provided in section 235-54 shall be allowed only to the extent of the ratio of the adjusted gross income attributed to this State to the entire adjusted gross income computed without regard to source in the State.
(e) If in the opinion of the department the allocations hereinabove provided do not clearly and accurately reflect the actual amount of the adjusted gross income and taxable income received or derived from all property owned and any and every other source in the State, or if any person shows that the allocations hereinabove provided result in adjusted gross income or taxable income being attributed to the State in a larger amount than is just and equitable, then the same shall be determined, allocated, and apportioned under such rules, processes, and formulas as the department prescribes as being just and equitable.

[L Sp 1957, c 1, pt of §2; am L Sp 1959 2d, c 1, §16; Supp, §121-4; HRS §235-5; am L 1978, c 173, §2(6); am L 1983, c 88, §2; gen ch 1985; am L 1989, c 11, §1; am L 1999, c 253, §3]