(b) The city taxable income for the portion of the year during which an individual described in subsection (a) is a city resident individual shall be determined, except as provided in subsection (c), under the rules provided in section six hundred thirty-eight of this chapter, as if he were computing his New York taxable income and his taxable year for New York state personal income tax purposes were limited to the period of his city resident status.

(c) When an individual changes his status from city resident to city nonresident, or from city nonresident to city resident, he shall, regardless of his method of accounting, accrue any items of income, gain, loss, deduction or ordinary income portion of a lump sum distribution accruing prior to the change of status, with the applicable modifications and adjustments to federal adjusted gross income and itemized deductions under sections six hundred twelve and six hundred fifteen, if not otherwise properly includible or allowable for New York income tax purposes for such period or a prior taxable year under his method of accounting. Such accruals shall be made as provided in section six hundred thirty-nine of this chapter.

(d) Trusts. If the status of a trust changes during its taxable year from city resident to city nonresident, or from city nonresident to city resident, the fiduciary shall file one return as a city resident trust for the portion of the year during which the trust is a city resident trust, and a return under a local law for the portion of the year during which the trust is a city nonresident trust, subject to such exceptions as the state tax commission may prescribe by regulations.

(e) The city taxable income for the portion of the year during which a trust described in subsection (d) is a city resident trust shall be determined, except as provided in subsection (c), under the rules provided in section six hundred thirty-eight of this chapter, as if its New York taxable income were being computed and its taxable year for New York state personal income tax purposes were limited to the period of its city resident status.

(f) When the status of a trust changes from city resident to city nonresident, or from city nonresident to city resident, it shall, regardless of its method of accounting, accrue any items of income, gain, loss or deduction accruing prior to the change of status. Such accruals shall be made as provided in section six hundred thirty-nine of this chapter.