RCW 82A.04.410: Allocation and apportionment—Generally.

(1) For resident individuals, all income must be allocated to this state.

(2) For nonresident individuals, income derived from sources within this state must be allocated to this state. Income derived from sources within this state means:

(a) Wages and other compensation from employment within this state as provided in RCW 82A.04.430;

(b) Compensation attributable to professional athletics as provided in RCW 82A.04.435;

(c) Income of a nonresident student athlete derived from the commercial use of the student athlete's name, image, or likeness as provided in RCW 82A.04.460;

(d) Amounts attributable to any business, trade, profession, or occupation carried on within this state, including an individual's distributive share of income from a pass-through entity operating within this state as provided in RCW 82A.04.420, to the extent determined under RCW 82A.04.440;

(e) Rents, short-term gains, and other amounts attributable to the ownership or disposition of any interest in real or tangible personal property in this state;

(f) Income from intangible personal property, including annuities, dividends, interest, and gains from the disposition of intangible personal property, to the extent that the intangible personal property was employed in a business, trade, profession, or occupation carried on within this state; and

(g) Income received from wagering transactions.

(3) If the nonresident individual performs services in Washington five or fewer days cumulatively in any calendar year, no income must be allocated pursuant to this section. This subsection (3) does not apply to nonresident professional athletes, nonresident student athletes, and nonresident entertainers.

(4) Deductible expenses, capital losses, and net operating losses of a nonresident are based solely on income, gains, losses, and deductible expenses derived from or connected with sources in this state but are otherwise determined in the same manner as the corresponding federal deductions except as provided in this chapter.

(5) Compensation paid by the United States for service in the armed forces of the United States performed in this state by a nonresident does not constitute income derived from sources within this state.

(6) Income earned by a nonresident participating as a keynote speaker, panelist, presenter, moderator, or similar role at a convention trade show or business event held in this state may be excluded if the individual meets the requirements of RCW 82.32.531.