Bloomberg BSYM Omits Historical Tickers from Current Security Lists
Summary
The document explains why a current Bloomberg BSYM equity list may not show every ticker historically associated with a company. Its examples involve the letter V, which has been used by both Vivendi and Visa at different times, and Chrysler's former DCX ticker. A current list can therefore appear complete while omitting delisted companies or older symbols.
The answer says BSYM associates a security with its last known ticker and does not publish every historical ticker linked to that security. It describes Bloomberg identifiers as searchable and unique, while noting that access to the API is needed to avoid survivorship bias when reconstructing historical securities. The discussion is brief and does not provide a procedure for obtaining the full history or assess other data sources, so researchers should treat a current ticker list as insufficient evidence of historical coverage.
Key ideas
- A current security list can omit tickers belonging to delisted companies.
- A security identifier may remain unique even when its associated ticker changes over time.
- The response says BSYM exposes the last known ticker rather than every historical symbol.
- Historical research needs data with survivorship-bias-free ticker and security coverage.
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Full text
# BSYM for historical tickers # BSYM for historical tickers When looking through Bloomberg's BSYM data ADR and Common Stock data (5/2/13), I was able to find the ticker symbol 'V' associated with Visa but was unable to find any record for Vivendi, which I believe also used 'V' at some point in time. If BSYM is a truly unique identifier (which interests me since it's an open-source way to have a unique security ID), shouldn't I see at least one record for the Vivendi Universal ADR that also had the 'V' symbol? ===EDIT=== Here's a more clear example: Chrysler used to trade under "DCX" (after they were bought by Daimler) ... that ticker appears nowhere in the Bloomberg BSYM data. So I'm assuming that a current view of the BSYM equity/common-stock list has survivorship issues (i.e. it's a great source of all current tickers but won't include any companies that no longer exist). ## Answer by Michael WS (score 1) https://quant.stackexchange.com/a/8385 bloomberg symbology returns the last known ticker and associates that with a bbgid. They do not release all of the associated tickers with data. There is no way of finding out all of the historical tickers associated with an entity. bloomberg publishes bbgid's which are "open" by searching and unique but you need api access to become survivorship bias free. ## Answer by franktheshark (score 0) https://quant.stackexchange.com/a/7896 Your answer is found on Wikipedia, > Symbols sometimes change to reflect mergers. Prior to the 1999 merger with Mobil Oil, Exxon used a phonetic spelling of the company "XON" as its ticker symbol. The symbol of the firm after the merger was "XOM". Symbols are sometimes reused, in the US the single letter symbols are particularly sought after as vanity symbols. For example since Mar 2008 Visa Inc. has used the symbol V that had previously been used by Vivendi which had delisted and given up the symbol. [1] Here is a list of current registered Vivendi symbols on Bloomberg.
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