Section 40-b - Redemption by mortgagee1.The holder of any mortgage which is duly recorded at the time of the sale, may, at any time after the sale of all or any part of the mortgaged premises for unpaid taxes or assessments, and before the expiration of six months after the time of filing of the evidence of the giving of the notice required by the preceding section, or, if the notice required by such section is not given or, if evidence of the giving of such notice be not filed then at any time within thirty-six months after the sale, and not thereafter, redeem the premises so sold, or any part thereof from such sale. The redemption shall be made by filing with the county treasurer a written description of his mortgage, and by paying to the county treasurer, upon the certificate of the county treasurer, for the use of the purchaser, or those claiming under him, the same amount which such holder would be required to pay upon redemption of such premises if he were an occupant thereof. In case of failure to redeem within the time herein specified, the sale and conveyance thereof shall become absolute and the mortgagee and all other persons claiming title by virtue of any mortgage barred forever. The holder of such mortgage shall have a lien upon the premises redeemed for the amount so paid with interest from the time of payment, in like manner as if it had been included in the mortgage.2.This section shall apply to sales made prior to March twenty-ninth, nineteen hundred fifty, as well as to sales made on or after that date, except that the holder of any mortgage on property sold for unpaid taxes prior to that date who still has a right to redeem under the statutes in effect at the time of such sale, whether or not notice to redeem was given or evidence of such notice filed, may redeem within twelve months after this act takes effect, and not thereafter.N.Y. Suffolk County Tax Act § 40-b