Lineage

Lineage (or data lineage) is the traceable path from a reported number back through every transformation and calculation to the raw source data it came from.

In finance, lineage is what makes a figure defensible: in diligence, in audit, or in front of a board, you can show exactly how a number was built.

What lineage covers

A complete lineage record answers four questions about a figure. Which source records fed it. Which transformations touched it, in order, including mapping, currency translation, allocation, and elimination. Which version of the calculation logic ran. And when each of those happened, so a restated figure can be distinguished from a corrected one.

Lineage differs from an audit trail in direction. An audit trail records what people and systems did, chronologically. Lineage records how a specific number was assembled, structurally. You need both, but only lineage answers “why is this cell what it is.”

Why lineage breaks in practice

Most finance stacks lose lineage at the seams. Data leaves the ERP with lineage intact, lands in a spreadsheet, and the moment someone hardcodes a value or pastes a range, the chain is severed with no marker that it happened. Allocation and expense allocation steps are another common break: a driver-based split spreads one balance across twelve cost centers, and if the driver isn’t versioned, the split cannot be reproduced later.

Aggregation loses it too. A figure summed at group level in a BI tool often carries no path back to the entity-level entries, so answering a board question means rebuilding the rollup from scratch. And AI layers bolted on top of that stack inherit the gaps: a model can only cite what the underlying system preserved.

Lineage as an AI prerequisite

An AI assistant that reports figures is only as checkable as the lineage beneath it. Without it, every answer is a black-box answer regardless of how well the model explains itself, because there is nothing underneath to check the explanation against. With it, a citation is a verifiable claim rather than a formatting convention.

Rexfin preserves lineage on every figure in the model: sources reconcile into one governed model, each calculation runs deterministically so it can be replayed, and any figure drills through its transformations to the source record behind it. See our approach to security and trust.