Incomplete Instrument Law and Legal Definition
Incomplete instrument is a signed writing, the contents of which show that at the time of signing it is incomplete, but that the signer intended it to be completed by the addition of words or numbers. An incomplete instrument can be issued by the signer or any other person. When the words or numbers are added to an incomplete instrument without authority of the signer, there is an alteration. It can be enforced according to its terms if it is not completed or according to its terms as augmented by completion. The burden of establishing that words or numbers were added to an incomplete instrument without authority of the signer is on the person asserting lack of authority.