Section 133 - Additions to tax and civil penalties(a) Failure to file tax return.-In case of failure to file a tax return under this title on or before the prescribed date (determined with regard to any extension of time for filing), unless it is shown that such failure is due to reasonable cause and not due to willful neglect, there shall be added to the amount required to be shown as tax on such return five per cent of the amount of such tax if the failure is for not more than one month, with an additional five per cent for each additional month or fraction thereof during which such failure continues, not exceeding twenty-five per cent in the aggregate. For this purpose, the amount of tax required to be shown on the tax return shall be reduced by the amount of any part of the tax which is paid on or before the date prescribed for payment of the tax and by the amount of any credit against the tax which may be claimed upon the return.(b) Deficiency due to negligence.-If any part of a deficiency is due to negligence or intentional disregard of this title or rules or regulations hereunder (but without intent to defraud), there shall be added to the tax an amount equal to five per cent of the deficiency.(c) Failure to file declaration or underpayment of estimated tax.-If any taxpayer fails to file a declaration of estimated tax or fails to pay all or any part of an installment of estimated tax, he shall be deemed to have made an underpayment of estimated tax. There shall be added to the tax for the taxable year an amount at the rate set by the commissioner of finance pursuant to section one hundred forty-five, or, if no rate is set, at the rate of six per centum per annum upon the amount of the underpayment for the period of the underpayment but not beyond the fifteenth day of the fourth month following the close of the taxable year. The amount of underpayment shall be the excess of the amount of the installment which would be required to be paid if the estimated tax were equal to ninety per cent of the tax shown on the return for the taxable year (or if no return was filed, ninety percent of the tax for such year) over the amount, if any, of the installment paid on or before the last day prescribed for such payment. No underpayment shall be deemed to exist with respect to a declaration or installment otherwise due on or after the taxpayer's death. In any case in which there would be no underpayment if this subdivision were applied by substituting "eighty percent" for "ninety percent" where it appears in the second preceding sentence, the addition to tax under this subdivision shall be equal to seventy-five percent of the amount otherwise determined under this subdivision.(d) Exception to addition for underpayment of estimated tax.-The addition to tax under subdivision (c) with respect to any underpayment of any installment shall not be imposed of the total amount of all payments of estimated tax made on or before the last date prescribed for the payment of such installment equals or exceeds whichever of the following is the lesser- (1) The amount which would have been required to be paid on or before such date if the estimated tax were whichever of the following is the least-(A) The tax shown on the return of the taxpayer for the preceding taxable year, if a return showing a liability for tax was filed by the taxpayer for the preceding taxable year and such preceding year was a taxable year of twelve months, or(B) An amount equal to the tax computed, at the rates applicable to the taxable year, but otherwise on the basis of the facts shown on his return for, and the law applicable to, the preceding taxable year, or(C) An amount equal to ninety per cent of the tax for the taxable year computed by placing on an annualized basis the unincorporated business taxable income for the months in the taxable year ending before the month in which the installment is required to be paid. For purposes of this subparagraph, the unincorporated business taxable income shall be placed on an annualized basis by- (i) multiplying by twelve (or, in the case of a taxable year of less than twelve months, the number of months in the taxable year) the unincorporated business taxable income for the months in the taxable year ending before the month in which the installment is required to be paid, and(ii) dividing the resulting amount by the number of months in the taxable year ending before the month in which such installment date falls, or(D)(i) If the base period percentage for any six consecutive months of the taxable year equals or exceeds seventy percent, an amount equal to ninety percent of the tax determined in the following manner-(I) take the unincorporated business taxable income for all months during the taxable year preceding the filing month,(II) divide such amount by the base period percentage for all months during the taxable year preceding the filing month,(III) determine the tax on the amounts determined under subclause (II), and(IV) multiply the tax determined under subclause (III) by the base period percentage for the filing month and all months during the taxable year preceding the filing month.(ii) For purposes of clause (i)- (I) the base period percentage for any period of months shall be the average percent which the unincorporated business taxable income for the corresponding months in each of the three preceding years bears to the unincorporated business taxable income for the three preceding taxable years. The commissioner of finance may by regulations provide for the determination of the base period percentage in the case of new unincorporated businesses and other similar circumstances, and(II) the term "filing month" means the month in which the installment is required to be paid; or(2) An amount equal to ninety percent of the tax computed, at the rates applicable to the taxable year, on the basis of the actual unincorporated business taxable income for the months in the taxable year ending before the month in which the installment is required to be paid.(e) Allocation of unincorporated business tax.- (1)Except as provided in paragraph two hereof, subparagraphs (A) and (B) of paragraph one of subdivision (d) of this section shall not apply in the case of any taxpayer which had unincorporated business taxable income, or the portion thereof allocated within the city, of one million dollars or more for any taxable year during the three taxable years immediately preceding the taxable year involved.(2) The amount treated as the estimated tax under subparagraphs (A) and (B) of paragraph one of subdivision (d) of this section shall in no event be less than seventy-five percent of the tax shown on the return for the taxable year beginning in nineteen hundred eighty-three or, if no return was filed, seventy-five percent of the tax for such year.(f) Deficiency due to fraud.-If any part of a deficiency is due to fraud, there shall be added to the tax an amount equal to fifty per cent of the deficiency. This amount shall be in lieu of any other addition to tax imposed by subdivision (a) or (b).(g) Additional penalty.-Any taxpayer who with fraudulent intent shall fail to pay any tax, or to make, render, sign or certify any return or declaration of estimated tax, or to supply any information within the time required by or under this title, shall be liable to a penalty of not more than one thousand dollars, in addition to any other amounts required under this title, to be imposed assessed and collected by the director of finance. The director of finance shall have the power, in his discretion, to waive, reduce or compromise any penalty under this subdivision.(h) Additions treated as tax.-The additions to tax and penalties provided by this section shall be paid upon notice and demand and shall be assessed, collected and paid in the same manner as taxes, and any reference in this title to income tax or tax imposed by this title, shall be deemed also to refer to the additions to tax and penalties provided by this section. For purposes of section one hundred twenty-nine, this subdivision shall not apply to- (1) any addition to tax under subdivision (a) except as to that portion attributable to a deficiency;(2) any addition to tax under subdivision (c); and(3) any additional penalty under subdivision (g).(i) Determination of deficiency.-For purposes of subdivisions (b) and (f), the amount shown as the tax by the taxpayer upon his return shall be taken into account in determining the amount of the deficiency only if such return was filed on or before the last day prescribed for the filing of such return, determined with regard to any extension of time for such filing.(j) Substantial understatement of liability.-If there is a substantial understatement of tax for any taxable year, there shall be added to the tax an amount equal to ten percent of the amount of any underpayment attributable to such understatement. For purposes of this subdivision, there is a substantial understatement of tax for any taxable year if the amount of the understatement for the taxable year exceeds the greater of ten percent of the tax required to be shown on the return for the taxable year, or five thousand dollars. For purposes of the preceding sentence, the term "understatement" means the excess of the amount of the tax required to be shown on the return for the taxable year, over the amount of the tax imposed which is shown on the return. The amount of the understatement under the preceding sentence shall be reduced by that portion of the understatement which is attributable to the tax treatment of any item by the taxpayer if there is or was substantial authority for such treatment, or any item with respect to which the relevant facts affecting the item's tax treatment are adequately disclosed in the return or in a statement attached to the return. The commissioner of finance may waive all or any part of the addition to tax provided by this subdivision on a showing by the taxpayer that there was reasonable cause for the understatement (or part thereof) and that the taxpayer acted in good faith.N.Y. General City Model Law § 133