N.Y. TAX Law § 254

§ 254. Optional tax on prior mortgages. Whenever any mortgage other\nthan a mortgage specified in section two hundred and sixty-four has been\nrecorded prior to July first, nineteen hundred and six, the record owner\nthereof may file with the recording officer of the county in which the\nreal property, or any part thereof, on which said mortgage is a lien, is\nsituated, a written statement under oath verified by the record owner or\nthe agent or officer of such record owner describing such mortgage by\ngiving the date of the same and the liber and page of the record thereof\ntogether with the names of the parties thereto, specifying the amount\nthen remaining unpaid on the debt or obligation secured thereby, and\nelecting that it shall become subject to the tax prescribed by section\ntwo hundred and fifty-three of this chapter. Whenever any unrecorded\nmortgage has been executed and delivered prior to July first, nineteen\nhundred and six, the owner thereof may record the same upon filing with\nthe recording officer a similar statement and paying the tax as herein\nprescribed. A tax shall thereupon be computed, levied and collected upon\nthe amount of the principal debt or obligation unpaid at the time of the\nfiling of such statement, or of the recording of such mortgage and\nfiling of such statement. On the payment of such tax as herein provided,\nthe recording officer shall note on the margin of the record of such\nmortgage the fact of such statement and of the amount of the tax paid,\nattested by his signature, whereupon such mortgage and the debt or\nobligation secured thereby shall be entitled to the exemptions and\nimmunities conferred by this article, and all of the provisions of this\narticle shall thereafter be applicable to said mortgage. Whenever the\noriginal mortgage is presented to the clerk together with the statement\nhe shall also note on said original mortgage the fact of the filing of\nthe said statement and also the amount of the tax paid duly attested by\nhis signature, which indorsement shall be conclusive evidence of the\npayment of such tax.\n