N.Y. Tax Law § 264
Whenever any part of the amount of the principal indebtedness which is or under any contingency may be secured by a mortgage recorded prior to July first, nineteen hundred and six, is advanced after July first, nineteen hundred and six, the tax prescribed by section two hundred and fifty-three of this article is hereby imposed on the amount of principal indebtedness so advanced, which tax shall be payable at the same time and in the same manner as taxes imposed by section two hundred and fifty-nine of this article, and all the provisions of section two hundred and fifty-nine in relation to the time and manner of paying such tax, the filing of statements in relation to the time and amount of such advances, and penalties for failure to file the same shall apply to advances made under this section and the payment of a tax thereon, except that if the mortgagor is not a corporation, such statements shall be filed by the owner of the mortgage, who, for failure to do so, shall be subject to the penalties prescribed by such section. In case said mortgage was given to secure the payment of a series of bonds, the mortgagor may, at the time of paying such tax, present to the recording officer, the bonds representing the portion of the principal indebtedness secured by said mortgage upon which the tax is to be paid, and also file with said recording officer a statement verified by the mortgagor or an officer or duly authorized agent or attorney of the mortgagor specifying that said bonds, so presented, are the bonds representing that portion of the principal indebtedness secured by said mortgage upon which the tax is to be paid and that said bonds are secured by a mortgage recorded in said office stating the date of said mortgage and the liber and page of the record of the same. It shall be the duty of such recording officer to indorse upon each of said bonds, so presented to him, a statement signed by him to the effect that the tax imposed by this article on that portion of the principal indebtedness secured by said mortgage represented by said bonds has been paid, and said statement shall be conclusive proof of such payment. Notwithstanding the exception contained in section two hundred and fifty-four, the record owner of any mortgage recorded prior to July first, nineteen hundred and six, other than a corporate trust mortgage, may file in the office of the recording officer where such mortgage is first recorded a statement in form and substance as required by section two hundred and fifty-four of this article, except that it shall specify and state the amount of all advancements made thereon prior to said date, giving the date and amount of each advancement and the amount of such prior advancements remaining unpaid, and thereby elect that the same be taxed under this article; and any mortgagor or mortgagee under a corporate trust mortgage given to secure a series of bonds or the owner of any such bond or bonds secured thereby may file in the office of the recording officer where such mortgage is first recorded a statement in form and substance as required by section two hundred and fifty-four of this article, except that it shall specify the serial number, the date and amount of each bond and otherwise sufficiently describe the same to identify it as being secured by such mortgage, and thereby elect that such bond or bonds be taxed under this article, and such bond or bonds shall be taxed upon the whole amount thereof notwithstanding the provisions of section two hundred and sixty of this article. A tax shall thereupon, in the case of mortgages other than corporate trust mortgages, be computed, levied and collected upon the amount of the principal debt or obligation represented by said unpaid prior advancements at the time of filing such statement, or, in the case of a corporate trust mortgage, upon the amount of the bond or bonds specified in the statement filed, at the rate prescribed by section two hundred and fifty-three of this article. Said bonds representing prior advancements under corporate trust mortgages and taxed as herein provided may be presented to the recording officer, whose duty it is to collect said tax, for indorsement and he shall thereupon indorse upon each of said bonds a statement, attested by his signature, of the payment of the tax as provided in this section in respect to bonds representing subsequent advancements, and the record owner of any other mortgage taxed upon prior advancements as herein provided may present said mortgage to the recording officer and thereupon such officer shall note upon the same the filing of the statement and the amount of the tax paid, attested by his signature. In all such cases the recording officer shall note on the margin of the record of such mortgage the filing of such statement and the amount of the tax paid, and, in case of bonds secured by corporate trust mortgages, the serial number of each such bond. The words "bond" and "bonds" as used in this section shall be deemed to embrace all notes or other evidences of indebtedness secured by mortgages taxable under this section. In case of any mortgage taxable under this section, the portion of the indebtedness secured thereby upon which the tax imposed by this section is paid, and such portion only, shall be exempt from taxation under the provisions of section two hundred and fifty-one of this article. Whenever the tax imposed by section two hundred and sixty-four of this article as said section existed prior to May thirteenth, nineteen hundred and seven, has been paid with respect to any mortgage, no additional tax shall accrue on such mortgage under this section as hereby enacted and such mortgage and the debt or obligation secured thereby, shall continue to be entitled to the exemptions and immunities conferred by this article and all of the provisions of this article shall remain applicable to such mortgage. All taxes imposed by or which became due, payable or collectible on or before the thirtieth day of June, nineteen hundred and six, pursuant to chapter seven hundred and twenty-nine of the laws of nineteen hundred and five, and all taxes which under section two hundred and fifty-eight of this chapter became due and payable on the thirtieth day of July, nineteen hundred and six, and all other taxes, if any, which were imposed by chapter seven hundred and twenty-nine of the laws of nineteen hundred and five on any mortgage recorded prior to the first day of July, nineteen hundred and six, in respect to any period ending on or before the first day of July, nineteen hundred and six, shall be imposed, become due, be payable and collectible and shall be paid over and distributed in the same manner, and with the same force and effect as if this article had not been enacted; and for the purpose of collecting, paying over, distributing and enforcing any such taxes, chapter seven hundred and twenty-nine of the laws of nineteen hundred and five shall be deemed to be in force, and the lien for such taxes shall attach and such taxes shall be levied and collected as provided in chapter seven hundred and twenty-nine of the laws of nineteen hundred and five, anything herein contained to the contrary notwithstanding.
N.Y. Tax Law § 264