N.Y. Comp. Codes R. & Regs. tit. 20, § 6-1.3
Tax Law, § 211(3)
(a) General.
If the amount of the taxable income of any taxpayer or of any shareholder of any taxpayer, that has elected to be taxed under subchapter S of chapter one of the Internal Revenue Code, as reported for Federal income tax purposes, is changed or corrected by a final determination of the Commissioner of Internal Revenue or other officer of the United States, or other competent authority, or if a renegotiation of a contract or subcontract with the United States results in a change in taxable income, the taxpayer is required to report such changed or corrected taxable income or the results of such renegotiation within 90 days, or 120 days in the case of a taxpayer making a combined report for the taxable year affected, after the final determination. The taxpayer must concede the accuracy of such determination or state wherein it is erroneous.
(b) Final determination.
Any deficiency notice issued (including a notice issued pursuant to a waiver filed by a taxpayer) pursuant to the provisions of the Internal Revenue Code is a final determination unless a timely petition to redetermine the deficiency is filed in the Tax Court of the United States. If a petition is filed, the judgment of the court of last resort is the final determination. The allowance by the Commissioner of Internal Revenue of a refund of any part of the tax shown on the taxpayer's return or of any deficiency thereafter assessed, whether the refund is made on the commissioner's own motion or pursuant to the judgment of a court, is also a final determination. The allowance of a tentative carry-back adjustment in accordance with section 6411 of the Internal Revenue Code based on a net operating loss carry-back or a net capital loss carry-back must be treated as a final determination.