Iglow A short by contract is a borrowed share it is not a real certificate only a contract to loan and borrow as soon as it is released there is another certificate it is based on the broker locating somebody that will loan out the certificate that certificate needs to be identified because it has a serial number if not the short loan certificate does not have any serial number it is now a fiat certoficate with the person that shorts it that is where the clearing company needs to match them up in my opinion