Fact tables that expose the full equation of proﬁt are among the most powerful deliverables of an enterprise DW/BI system. The equation of proﬁt is (revenue) – (costs) = (proﬁt). Fact tables ideally implement the proﬁt equation at the grain of the atomic revenue transaction and contain many components of cost. Because these tables are at the atomic grain, numerous rollups are possible, including customer proﬁtability, product proﬁtability, promotion proﬁtability, channel proﬁtability, and others. However, these fact tables are difficult to build because the cost components must be allocated from their original sources to the fact table’s grain. This allocation step is often a major ETL subsystem and is a politically charged step that requires high- level executive support. For these reasons, proﬁt and loss fact tables are typically not tackled during the early implementation phases of a DW/BI program.