Occurs when the security has been listed and posted for trading, but the certificate representing the security itself is not yet issued and available for settlement. The exchange bulletin issued on listing of the security indicates if the trading will be done on a when-issued basis. In this case, the issuance of the security is guaranteed and the delay in issuance is often due to factors relating to the printing and distribution of the security. The period for when-issued trading is usually less than one week.