(a) Report of change in Federal or New York State taxable income. (Administrative Code § 11-519)
If the amount of the taxpayer's Federal or New York State taxable income reported on the Federal or New York State income tax return is changed or corrected by the United States Internal Revenue Service or the New York State Department of Taxation and Finance or other competent authority, or changed as a result of a renegotiation of a contract or subcontract with the United States or the State of New York, or if the taxpayer, pursuant to subsection (d) of § 6213 of the Internal Revenue Code, executes a notice of waiver of the restrictions on assessment and collection provided in subsection (a) of said section of the Internal Revenue Code, or if a taxpayer, pursuant to subdivision (f) of § 681 of the New York Tax Law, executes a notice of waiver of the restrictions provided in subdivision (c) of said section of the New York Tax Law, and such change, correction or waiver pertains to the unincorporated business gross income or unincorporated business deductions of the taxpayer, a report of such change, correction or waiver, and the changes or correction in his Federal or New York State taxable income on which it is based, must be filed within ninety days after the final determination of such change, correction, or renegotiation, or such execution of such notice of waiver. The taxpayer shall concede the accuracy of such determination or state wherein it is erroneous. Any taxpayer filing an amended Federal or New York State income tax return shall also file within ninety days thereafter an amended return under these regulations for New York City unincorporated business tax purposes.
(b) Report of change of New York State sales and compensating use tax. (Administrative Code § 11-519.1)
Where the State Tax Commission changes or corrects a taxpayer's sales and compensating use tax liability with respect to the purchase or use of items for which a sales or compensating use tax credit against the tax imposed by Chapter 5 of Title 11 of the Administrative Code was claimed (see: 19 RCNY § 28-03(c)(3)), the taxpayer shall report such change or correction to the Commissioner of Finance within ninety days of the final determination of such change or correction, and shall concede the accuracy of such determination or state wherein it is erroneous. Any taxpayer filing an amended return or report relating to the purchase or use of such items shall also file within ninety days thereafter a copy of such amended return or report with the Commissioner of Finance.
(c) Form of report of change in Federal or New York State taxable income or New York State sales and compensating use tax liability. The report referred to in 19 RCNY § 28-20(a) shall be made on Form NYC-115. The report referred to in 19 RCNY § 28-20(b) shall be made on Form NYC-116. It must be accompanied by a copy of the final Federal or New York State determination or renegotiation agreement as well as any other pertinent data in all cases in which a refund based on such final determination or renegotiation agreement is claimed. Where additional tax is due, the taxpayer may, in lieu of a copy of the final determination or renegotiation agreement, give full details of the changes in taxable income on Form NYC-115 or the changes in sales and compensating use tax liability on Form NYC-116. The report on Form NYC-115 or Form NYC-116 shall be accompanied by full payment of any tax shown to be due thereon and shall be forwarded separately from, and not as part of, any other report or return. The report must be made by the taxpayer regardless of whether he believes any modification of his tax liability is required.
(d) Federal or New York State changes not binding. The Commissioner of Finance is not required to accept as correct any change in taxable income or sales and compensating use tax liability as hereinabove set forth, but may conduct an independent audit or investigation in regard thereto.
(e) Final determination. A final determination for purposes of this section includes but is not limited to the following instances:
(1) A closing agreement made under § 7121 of the Internal Revenue Code of 1954, or with the New York State Tax Commission, finally and irrevocably adjusting and settling a taxpayer's liability.
(2) An allowance by the Commissioner of Internal Revenue or the New York State Tax Commission of a refund of any part of the tax shown on the taxpayer's return or of any deficiency thereafter assessed, whether such refund is made on the Commissioner's or State Tax Commission's own motion or pursuant to a judgment of a court.
(3) The 90-day deficiency notice pursuant to § 6212 of the Internal Revenue Code of 1954 or § 681 of the Tax Law of the State of New York, or the 90-day Notice of Determination pursuant to § 1138 of the Tax Law of New York, unless a timely petition to redetermine the deficiency is filed in the Tax Court of the United States or with the New York State Division of Tax Appeals, in which event the judgment of the court of last resort affirming the deficiency, or the redetermination of the deficiency pursuant to a judgment of the court of last resort, is the final determination.
(4) The assessment of a deficiency pursuant to a waiver filed under § 6213 of the Internal Revenue Code of 1954 or § 681 of the Tax Law of the State of New York, where no 90-day deficiency notice is issued.
(5) The filing of a signed consent irrevocably and finally fixing sales and use tax liability under § 1138 of the Tax Law of the State of New York.
(f) Recomputation of tax. (Administrative Code § 11-523(c)(3) and (9) and § 11-527(c) and (k)). If the report of a change in Federal or New York State taxable income or New York State sales and compensating use tax liability or an amended New York City return conforming to an amended Federal or New York State return is filed after expiration of the period otherwise prescribed for assessment or refund, the amount of any assessment, credit or refund shall not exceed the increase or reduction in tax attributable to such Federal or New York State change or to the items amended on the taxpayer's amended Federal or New York State return.