N.Y. GCM Law § 101-A

§ 101-a. Taxable years to which tax applies; tax for taxable years\nbeginning prior to and ending after January first, nineteen hundred\nsixty-six. (a) General.--The tax imposed by section one hundred one,\nwith any modification permitted by subdivision (b) of this section, is\nimposed for each taxable year beginning with taxable years ending on or\nafter January first, nineteen hundred sixty-six.\n (b) Alternate methods for determining tax for taxable years ending on\nor after January first, nineteen hundred sixty-six.--(1) The tax for any\ntaxable year ending on or after January first, nineteen hundred\nsixty-six and before December thirty-first, nineteen hundred sixty-six,\nshall be an amount equal to the tax which would have been imposed had\nsection one hundred one been in effect for the entire taxable year,\nmultiplied by the number of months (or major portions thereof) in such\ntaxable year which occur after December thirty-first, nineteen hundred\nsixty-five and divided by the number of months (or major portions\nthereof) in such taxable year.\n (2) In lieu of the method of computation of tax prescribed in\nparagraph one, if the taxpayer maintained adequate records for the\nportion of any taxable year ending on or after January first, nineteen\nhundred sixty-six, and before December thirty-first, nineteen hundred\nsixty-six, which falls within the calendar year nineteen hundred\nsixty-six, the tax for such taxable year at the election of the taxpayer\nmay be computed on the basis of the unincorporated business taxable\nincome which the taxpayer would have reported had he filed a federal\nincome tax return for a taxable year beginning January first, nineteen\nhundred sixty-six and ending with the close of such taxable year ending\nbefore December thirty-first, nineteen hundred sixty-six. Such taxable\nyear beginning January first, nineteen hundred sixty-six and ending\nbefore December thirty-first, nineteen hundred sixty-six, shall be\ndeemed (unless clearly indicated otherwise) to be the taxable year of\nthe taxpayer. For purposes of this paragraph two, the unincorporated\nbusiness exemptions allowable under section one hundred nine, the credit\nallowable under subdivision (b) of section one hundred one and any net\noperating loss deduction as modified pursuant to subdivision two of\nsection one hundred six shall each be reduced by the same part of such\nexemptions, credit, or net operating loss deduction (as the case may be)\nas the number of months (or major portions thereof) in the taxable year\noccurring before January first, nineteen hundred sixty-six is of the\nnumber of months (or major portions thereof) in such taxable year.\nExcept as provided in this paragraph two, the tax for such period ending\nbefore December thirty-first, nineteen hundred sixty-six, shall be\ncomputed in accordance with the other provisions of this title.\n