R865-9I-6. Returns by Husband and Wife When One is a Resident and the Other is a Nonresident Pursuant to Utah Code Ann. Section 59-10-119

(1) Except as provided in Subsection (2), a husband and wife, one being a nonresident and the other a resident, who file a joint federal income tax return, but separate state income tax returns shall determine their separate:

(a) state taxable income as follows:

(i) Determine the amount of the total federal adjusted gross income ("FAGI") pertaining to each spouse. Any adjustments that apply to both spouses shall be divided between the spouses in proportion to the respective incomes of the spouses.

(ii) Allocate a portion of each deduction and add back item described in Section 59-10-114 to each spouse by:

(A) dividing each spouse's FAGI by the combined FAGI of both spouses, and rounding the resulting percentage to four decimal places; and

(B) multiplying the resulting percentage by any deductions and add back items described in Section 59-10-114; and

(b)(i) shares of the taxpayer tax credit authorized in Section 59-10-1018 by multiplying the percentage calculated under Subsection (1)(a)(ii)(A) by the:

(A) itemized or standard deduction; and

(B) state exemption for dependents.

(ii) For purposes of Subsection (1)(b)(i), each spouse shall claim his or her full state personal exemption.

(2) A husband and wife, one being a nonresident and the other a resident, may use an alternate method of calculating their separate state taxable incomes than the method provided in Subsection (1) if they can demonstrate to the satisfaction of the commission that the alternate method more accurately reflects their separate state taxable incomes.