Combining Exchange Identifiers with Stock Codes for Unique Symbols

Summary

The document addresses whether separate exchanges can assign the same code to different stocks. It explains that no general rule prevents this, even though exchanges often use distinct naming conventions. A ticker or stock code alone therefore may not uniquely identify an instrument across markets.

For software, spreadsheets, and data storage, the practical recommendation is to pair the code with an exchange identifier. In a database, both fields can form a composite key; code that requires a single identifier can construct one from the exchange and symbol. This is a data integrity principle for financial systems that combine listings from multiple venues. The answer is brief and does not discuss vendor-specific identifiers, symbol changes, share classes, or other cases where a richer instrument identifier may be necessary.

Key ideas

• Different exchanges can use the same stock code for different securities.
• Stock codes are not necessarily globally unique identifiers.
• Combining an exchange identifier with the stock code creates a more reliable key.
• A database can represent the pair as a composite key.

Tags

# Different stocks with the same stock code


# Different stocks with the same stock code












Is it possible to have different stocks with the same stock code on different stock exchanges.

## Answer by Phil H (score 4)

https://quant.stackexchange.com/a/3620

There is no reason that two different exchanges would be prevented from using the same code, although they usually have different conventions. So if you're writing code or spreadsheets that depend on a unique stock code, consider creating a unique code that combines the exchange identifier with the stock code. If this is in a database, use multiple keys in the table; include the exchange ID as one of the key fields.

So the answer is yes, it is possible.

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.