New York Consolidated Laws, Real Property Law - RPP § 412. When a transfer is deemed to be registered

Every transfer of registered property shall be deemed to be registered under this article when such document has been filed of record, in the office of the registrar of the county where the property is located and a serial number and certificate number has been assigned to the instrument; all other dealings shall be considered as registered when the document has been filed of record in the office of the registrar of the county where the property is located and a serial number and certificate number has been assigned the instrument.