The document describes how business areas are handled in various SAP FI modules. In general ledger accounting, business areas cannot be directly assigned to accounts but are derived from cost accounting assignments. In asset accounting, assets are assigned a single business area which then flows through to all related postings. In accounts receivable/payable, business areas come from the related revenue/expense postings. Cost accounting assigns business areas based on the master record of the cost element. Materials management assigns business areas based on the material's division and plant.