CUSIP code is not a constant, it could be changed. Does anybody know how to detect a CUSIP change? Is there any report with this info? Where can i find it? Thank you.
3 Answers
The framework that manages CUSIP assignment is proprietary and managed by CUSIP Global Services (a subsidiary of S&P Global). The CUSIP Global Services Master File is web-based platform & API system that provides a wide-range of CUSIP data points, including newly assigned identifiers at daily, weekly and even intraday increments. Without subscribing to the CSG Master File , there isn't an actively maintained, consolidated repository of CUSIP information available.
It should be noted however that CUSIP assignments do not simply "change". Think of a CUSIP like a barcode. Each CUSIP contains alpha-numerically enumerated information about a securities issuing entity (usually the first 6 digits, the "base"), and the specific security (7th and 8th digit, the "tail"). Once an equity issue, debt security etc. has been assigned a barcode, that barcode is unique and immutable.
CUSIP Structure: https://www.cusip.com/identifiers.html#/CUSIP
Accessing the CUSIP Master File: https://www.cusip.com/pdf/CGS079_CGS_CUSIP_Master_File_02_15_17_US_Ltr.pdf
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$\begingroup$ Equity cusip changes every time the company name changes (unlike, e.g. bonds). $\endgroup$ May 30, 2021 at 13:05
Use this form to search by old CUSIP:
https://quotes.fidelity.com/mmnet/SymLookup.phtml
the form will return - not found - if CUSIP changed.
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$\begingroup$ Thank you! But how often do they update their DB? I mean if a CUSIP was changed will this change be shown immediately or next day or next year? $\endgroup$– kbanDec 11, 2019 at 8:36
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$\begingroup$ CUSIP is as critical as Symbol. shall be updated with ~1day delay. $\endgroup$ Dec 25, 2019 at 8:47
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$\begingroup$ Hi: algoseek sells what is called their equity_security_master.csv that has all the information ( at whatever point in time you buy it ) for figuring out corporate actions. given a ticker or cusip today. I don't know if they sell it as a lone product or if you have to buy their data for them to sell it to you. I was buying data at the time I bought it. Note that, without that file, their historical data can't be mapped because the ticker is always as of that ( historical ) point in time. $\endgroup$ May 9, 2020 at 17:53
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$\begingroup$ Just to be clear, in the above, I used the term "today" and whatever point in time you buy it interchangeably. $\endgroup$ May 9, 2020 at 17:56
A stock cusip changes whenever the company name changes (unlike, e.g. bond cusips). In this case, you can assume that the old cusip and the new cusip refer to the same stock, and all the historical data is still applicable. But there may be other reasons for a cusip change, such as corporate mergers or spin-offs or re-organizations. You'd be better off using CRSP id (permo) or CompuStat gvkey as your primary identifier rather than a cusip.
If you must track cusip changes, I suggest you get this information from CRSP.