The CUSIPs that I have are as of the event date (events occur over many years). Given that the CUSIPs of some firms have changed over time, will the CUSIPERM option give me the correct PERMNO?
Yes, the design of CUSIPERM takes into account the fact that CUSIPs change over time. The PermnoUp program, which is run at Eventus installation and CRSP update installation, builds a conversion database by searching through the CRSP history of CUSIPs for each PERMNO. There should be no danger of obtaining an incorrect PERMNO for a given CUSIP. As the CRSP Data Description Guide states, “No header or historical CUSIPs are reused on our files.” Thus, each CUSIP is associated with a unique PERMNO. You may find that CUSIPERM fails to come up with any PERMNO in a few cases. There are two possible reasons for this. First, another database, from which the researcher obtained the CUSIP, may list the firm under a different CUSIP than CRSP does. This happens nontrivially often with a well-known financial statement database. In this case, one can manually search for the correct PERMNO Return to list of FAQ topics = 3 )) || ((navigator.appName == “Microsoft Internet Explorer”) && (parseInt(naviga
