Hi MM, For securities that are no longer trading we move them to a holding area that is away from the normal securities database.
For users that subscribe to our delisted historical data (which goes back to 1950) we change the symbol of the delisted security to represent its delisting date (e.g. Enron eventually delisted as ENRNQ in November 2004, so its symbol is ENRNQ-200411). By changing the symbol we avoid symbol overlaps. Symbol overlaps are important with a delisted database For example, the symbols AB, CDS, CSA, ENT and SEM have each been used 6 times since 1950. There were 48 securities delisted today on the US markets so this is quite a common event. I'd say there are an average of 15 securities each day that are delisted. Further issues remain with respect to annotations on charts within AmiBroker and symbol changes. This is due, in part, to the way that AmiBroker uses the traded code as the sole identifier for a security. Internally we use a unique numerical identifier which never changes even if a security changes its code, exchange or listed status. It would be great to work with Tomasz to enhance the AmiBroker chart database structure to provide a more robust method for matching securities on the basis of an identifier rather than the code. Best regards, Richard Dale. Norgate Investor Services - Premium quality Stock, Futures and Foreign Exchange Data for markets in Australia, Asia, Canada, Europe, UK & USA - www.premiumdata.net From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of marketmonk777 Sent: Wednesday, 4 June 2008 11:09 AM To: [email protected] Subject: [amibroker] Re: JimSwindle> US STOCKS DATABASE UPDATE Richard, How do you handle stocks that are no longer trading? I mean how do you notify your customer base? Or do you just remove it from their hard drives? As I mentioned earlier I use to use TC2005 (prior to finding Amibroker) and was using the chart notes feature to "log" all of my trades. What I discovered was that the Wordens would automatically remove dead symbols and therefore I would not be able to retrieve those notes and charts. That got me a little tweaked. Regards, MM
