Tax Law, § 632(b)(3)
Example:
Taxpayer A, a nonresident of New York State for the entire taxable year 1982, had a long-term capital gain from sources without New York State (from the sale of securities) of $20,000 on his Federal income tax return. A also included on his Federal income tax return a long-term capital loss of $8,000 from sources exclusively within New York State (from the sale of owned rental property). For Federal income tax purposes, A has a gain from the sale or exchange of property of $12,000 ($20,000 minus $8,000). On his New York State nonresident personal income tax return, A has only a long-term capital loss of $8,000 as this is the only capital item derived from New York State sources. A is allowed to claim a maximum capital loss deduction of $3,000 on his 1982 New York State nonresident personal income tax return and is allowed a $2,000 long-term capital loss carryover for the following year for New York State personal income tax purposes even though his 1983 Federal income tax return will show no capital loss carryover.
N.Y. Comp. Codes R. & Regs. Tit. 20 § 132.7