Point-In-Time symbols (PIT-Symbols)

PIT-Symbol (Point-In-Time Symbol) is a permanent and unique identifier for financial instruments (stocks, ETFs) used by CorrGrid. It addresses the key issue of frequent changes in stock tickers.

Standard stock tickers are not permanent: they change due to mergers, rebranding, and delistings. Furthermore, a ticker symbol can be reassigned to a completely different company once it becomes available, causing significant confusion in historical data analysis.

PIT-Symbol ensures a reliable and immutable link to a specific instrument throughout its entire history.

An arbitrarily chosen reference date in the past is set:

• CorrGrid uses 2022-01-01 as the Base Date.
  
  

For securities:

1. trading or listed on the Base Date:
   • PIT-Symbol = [Ticker at Base Date]_[Base Date].
         Examples: MSFT_2022-01-01, AAPL_2022-01-01.
2. delisted before Base Date:
   • PIT-Symbol = [Last Known Ticker]_[Date of Last Trade/Delisting].
         Example: ABCD_2015-02-17.
3. listed after Base Date (IPO, listing):
   • PIT-Symbol = [Ticker at Listing Date]_[Date of Listing/First Trade].
         Example: ARM_2023-09-14.
     
     

The system primarily aims for unambiguous identification of instruments within a specific database.

The accuracy of PIT-Symbol assignment depends on the provider’s historical data completeness (e.g., whether pre-market trading under tickers with w suffix or post-delisting OTC trading with Q suffix is included).

The following statements apply only when using the same Base Date. Therefore, we suggest using 2022-01-01 as a universal Base Date for all interested providers.

• Even if two different services assign different first or last trading dates to the same instrument due to differing data coverage, this doesn’t violate the core principle.
• Merging data from different systems remains possible, as identification uniqueness within each system is maintained. Furthermore, instances where different databases generate different PIT-Symbols for the same instrument are rare, and mapping them can typically be handled manually.

The PIT-Symbol ABCD_2015-02-17 uniquely identifies an instrument by its last ticker (ABCD) and last trading date on the primary exchange (2015-02-17) according to one database.

If another, more comprehensive database also tracks subsequent OTC trading under the ticker ABCDQ until final liquidation on 2015-03-23, it might assign the PIT-Symbol ABCDQ_2015-03-23. When synchronizing these databases, a mapping can be established between ABCD_2015-02-17 and ABCDQ_2015-03-23, as both refer to the evolution of the same underlying instrument. Such discrepancies are rare.

• Advantages:
  • Permanence
  • Uniqueness (resolves issues from ticker changes and reuse), intuitiveness (clearer than alternatives like JPM1, JPM2 or 8743JPM4hKLJHFN, DHPAMSFT87GH)
  • Algorithmic reliability
  • Historical consistency.
• Disadvantages:
  • Identifiers are longer than standard tickers.
  • Requires historical data
    
    

The CorrGrid API provides a mapping mechanism for current tickers (as of any date) to their persistent PIT-Symbols via the instruments endpoint.