The company's real Business_Accounting_NO as returned by the registry. Populated only once the registry has positively identified exactly one real company for this row (the billable resolved row, a partial_source_coverage row that got at least that far, and a duplicate_entity row naming which already-billed company this repeat pointed at). Deduplication is per RUN: submitting the same company twice in one run is free the second time, but submitting it by number in one run and by name in another run is charged in each run, because the delivery journal is keyed on the submitted text rather than the resolved company. Null on every other free outcome: a number that never passed the checksum is not a real UBN, and a search that found zero or more than one candidate never identified a single company to name.