Use cases & endpoints
ISIN to ticker resolution API (instruments, dated)
An ISIN identifies a security; a ticker identifies how that security is displayed on a particular venue. One ISIN can trade under different symbols in different places, and one symbol can be reassigned to an entirely different company after a delisting. Neither fact is unusual, and both break naive joins.
The failure mode is quiet. A price series joined by symbol to a holdings file from six years ago produces a plausible-looking result that silently mixes two companies, and nothing in the output signals that anything went wrong.
Hindcast resolves instruments through dated mappings: ISIN to venue-specific symbols, with the period each mapping was valid, and links up to the issuing entity. Historical queries return the symbol that was in use then, which makes the join correct by construction rather than correct if you remembered to check.
hindcast — session
previewhindcast> which symbol did this ISIN trade under in a past year?
→ tool: entity_resolve { id:"...", type:"isin", as_of:"..." }
✓ venue symbols valid on that date, with the issuing entity
source: instrument and listing records, mappings dated
What's covered
- ISIN to venue symbol mappings with validity periods
- Multiple listings per instrument across venues
- Symbol reassignment handled by date rather than overwritten
- Instruments linked upward to the issuing entity
- CUSIP cross-references where available
- Delisted instruments retained and resolvable
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Questions
Why not just join on ticker?
Because tickers are display strings, not identifiers. They get recycled after delistings, differ across venues for the same security, and change with corporate actions — three independent ways for a join to be wrong without erroring.
Does this cover delisted securities?
Yes. A delisted instrument keeps its identifiers and its final mappings, which is what makes a survivorship-aware historical universe reconstructable.
Related
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