Nonresidents and part-year residents.

For taxable years beginning after December 31, 1997, and before January 1, 2000, with respect to nonresident individuals, including individuals changing their domicile into or from this state, the tax brackets under subs. (1m) and (2) (c) and (d) [s. 71.06 (1m), 2023 stats., s. 71.06 (2) (c), 2023 stats., and s. 71.06 (2) (d), 2023 stats.,] shall be multiplied by a fraction, the numerator of which is Wisconsin adjusted gross income and the denominator of which is federal adjusted gross income. In this paragraph, for married persons filing separately “adjusted gross income” means the separate adjusted gross income of each spouse, and for married persons filing jointly “adjusted gross income” means the total adjusted gross income of both spouses. If an individual and that individual’s spouse are not both domiciled in this state during the entire taxable year, the tax brackets under subs. (1m) and (2) (c) and (d) [s. 71.06 (1m), 2023 stats., s. 71.06 (2) (c), 2023 stats., and s. 71.06 (2) (d), 2023 stats.,] on a joint return shall be multiplied by a fraction, the numerator of which is their joint Wisconsin adjusted gross income and the denominator of which is their joint federal adjusted gross income.

For taxable years beginning after December 31, 1999, and before January 1, 2001, with respect to nonresident individuals, including individuals changing their domicile into or from this state, the tax brackets under subs. (1n) and (2) (e) and (f) [s. 71.06 (1n), 2023 stats., s. 71.06 (2) (e), 2023 stats., and s. 71.06 (2) (f), 2023 stats.,] shall be multiplied by a fraction, the numerator of which is Wisconsin adjusted gross income and the denominator of which is federal adjusted gross income. In this paragraph, for married persons filing separately “adjusted gross income” means the separate adjusted gross income of each spouse, and for married persons filing jointly “adjusted gross income” means the total adjusted gross income of both spouses. If an individual and that individual’s spouse are not both domiciled in this state during the entire taxable year, the tax brackets under subs. (1n) and (2) (e) and (f) [s. 71.06 (1n), 2023 stats., s. 71.06 (2) (e), 2023 stats., and s. 71.06 (2) (f), 2023 stats.,] on a joint return shall be multiplied by a fraction, the numerator of which is their joint Wisconsin adjusted gross income and the denominator of which is their joint federal adjusted gross income.

For taxable years beginning after December 31, 2000, with respect to nonresident individuals, including individuals changing their domicile into or from this state, the tax brackets under subs. (1p), (1q), (1r), and (2) (g), (h), (i), (j), (k), and (L) [subs. (1q), (1r), and (2) (i), (j), (k), and (L) and s. 71.06 (1p), 2023 stats., s. 71.06 (2) (g), 2023 stats., and s. 71.06 (2) (h), 2023 stats.,] shall be multiplied by a fraction, the numerator of which is Wisconsin adjusted gross income and the denominator of which is federal adjusted gross income. In this paragraph, for married persons filing separately “adjusted gross income” means the separate adjusted gross income of each spouse, and for married persons filing jointly “adjusted gross income” means the total adjusted gross income of both spouses. If an individual and that individual’s spouse are not both domiciled in this state during the entire taxable year, the tax brackets under subs. (1p), (1q), (1r), and (2) (g), (h), (i), (j), (k), and (L) [subs. (1q), (1r), and (2) (i), (j), (k), and (L) and s. 71.06 (1p), 2023 stats., s. 71.06 (2) (g), 2023 stats., and s. 71.06 (2) (h), 2023 stats.,] on a joint return shall be multiplied by a fraction, the numerator of which is their joint Wisconsin adjusted gross income and the denominator of which is their joint federal adjusted gross income.