N.Y. Real Prop. Law § 266
This article does not in any manner affect or impair the title of a purchaser or incumbrancer for a valuable consideration, unless it appears that such purchaser or incumbrancer had previous notice, whether actual or constructive, of the fraudulent intent of his immediate grantor, or of the fraud rendering void the title of such grantor. There shall be a rebuttable presumption that a purchaser or incumbrancer had notice of fraud or fraudulent intent in the case of a transfer of mortgaged real property, between a purchaser and seller who are not associated parties, that is not accompanied by the recording with the clerk of the county or with the commissioner of deeds in which the property is located, of a statement, executed by the mortgagee, and duly acknowledged, stating, substantially, that (a) a party is assuming the seller's indebtedness secured by the mortgage; or (b) that the indebtedness secured by the mortgage has been satisfied.
For the purposes of this section, "associated parties" means spouses, ex-spouses, parents and children, siblings, a homeowner and that homeowner's family trust, or a homeowner and that homeowner's wholly-owned limited liability company.
N.Y. Real Prop. Law § 266