Market and Model Versioning
Snapshot IDs and model IDs make valuations reproducible months later.
Market snapshots are immutable views of curves, vols, and fixings identified by snapshot IDs and timestamps.
Calibrated models carry model IDs linking model type, configuration, parameters, and the underlying market snapshot.
Valuation runs reference both snapshot and model IDs so that prices can be reproduced and audited.
Recalibration or data changes always produce new artefact IDs instead of silently mutating existing ones.
This timeline shows market snapshots, models, and valuation runs over several dates. Toggle between immutable IDs and mutation-in-place to see how lineage either preserves or erases the link between a past valuation and the snapshot and model it used.
With immutable snapshots and models, each valuation keeps the colour of the snapshot/model pair it used. Months later you can still say “P&L on t3 came from S2/M2” and re-run that setup.
Under mutation-in-place, all valuation markers drift to the latest colour: history collapses onto the newest snapshot. The mental model: IDs are not bureaucracy, they are lineage. If you overwrite artefacts instead of versioning them, you lose the audit trail that makes backtesting, controls, and regulatory defence possible.