13 Guam Code Ann. § 3405
(a) An imposter by use of the mails or otherwise has induced the maker or drawer to issue the instrument to him or his confederate in the name of the payee; or
(b) A person signing as or on behalf of a maker or drawer intends the payee to have no interest in the instrument; or
(c) An agent or employee of the maker or drawer has supplied him with the name of the payee intending the latter to have no such interest.
(2) Nothing in this section shall affect the criminal or civil liability of the person so indorsing.
§ 3406. Negligence Contributing to Alteration or Unauthorized
Signature.
Any person who by his negligence substantially contributes to a material alteration of the instrument or to the making of an unauthorized signature is precluded from asserting the alteration or lack of authority against a holder in due course or against a drawee or other payor who pays the instrument in good faith and in accordance with the reasonable commercial standards of the drawee’s or payor’s business.