LEARN. PRACTICE. GROW.Concept and mechanism
Reference data describes entities, instruments, and relatively stable conditions; market data contains observations whose meaning depends on context. An LEI identifies an entity and an ISIN identifies an instrument, but neither is a price. One entity can issue several instruments, and one instrument can have observations from several sources. Before joining records, confirm the identified object and matching rule. For prices, retain currency, unit, provenance, and relevant timestamp. Matching identifiers do not make currency-unit and cent-denominated values equivalent. Validation should make these distinctions explicit in the data contract and integration acceptance examples.
Guided application
Measure freshness in the data actually consumed, not only in provider connectivity. A recent heartbeat can coexist with old prices for part of a portfolio. Limits depend on instrument, session, and agreed policy; the five-minute limit in an exercise is a synthetic requirement. During a custodian change, manage settlement instructions with effective dates, approval, and consumer validation. An obsolete account can cause failures even when economic details agree. For cutover preparation, select positive cases, stale data, changed units, and partial updates. If an error occurs, scope affected derived results and reconcile before republication while preserving correction provenance.
Example: a quote changes from 42.50 to 4250 because the new provider uses cents. Confirm the contract before repairing the adapter and affected results.
Common pitfalls
LEI treated as instrument; ISIN treated as price assurance; heartbeat treated as freshness; unit correction applied indiscriminately.
Related topics: Trade lifecycle and responsibilities · FIX sessions and order state · Post-trade and settlement
Correct identity needs context, version, and consumed-data quality.
Reference: Identifiers · DR financial markets technology professional assessment2026.10