N.Y. U.C.C. 3-406

Section 3--406. Negligence Contributing to Alteration or Unauthorized\n Signature.\n Any person who by his negligence substantially contributes to a\nmaterial alteration of the instrument or to the making of an\nunauthorized signature is precluded from asserting the alteration or\nlack of authority against a holder in due course or against a drawee or\nother payor who pays the instrument in good faith and in accordance with\nthe reasonable commercial standards of the drawee's or payor's business.\n