Data Warehousing for Finance: The Financial Data Layer FP&A Actually Trusts

A company builds a data warehouse and the FP&A team doesn't use it. The reason is always the same: the warehouse numbers don't match the GL. The warehouse was loaded from the GL but doesn't include the final adjusting entries that landed after the extract. The account hierarchy doesn't match the hierarchy the controller uses for management reporting. The cost center dimension was mapped by IT without finance input. And when FP&A compares the warehouse P&L total to the trial balance, the difference is $47K that nobody can explain. The FP&A team doesn't have time to investigate — they need numbers they trust right now, not numbers they can probably trust after investigation. They go back to the GL.

Finance data warehousing done right makes trial balance reconciliation the first and most important deliverable. The warehouse loads from the post-close GL with all adjustments. The account and cost center hierarchies match the controller's structure exactly. The reconciliation job runs after every load and surfaces any variance before anyone uses the data. Planning data from Anaplan, Adaptive, or Oracle EPM is loaded alongside actuals for budget-to-actual analysis. Operational metrics from CRM, HRIS, and billing are joined through properly mapped dimensions. With the reconciliation in place, FP&A trusts the warehouse because it provably matches the GL. From there, all the analytical use cases become possible.