An automated accounting and reporting system supports flexible assignments of accounting objects to financial statements. At a reporting time, financial statement items may be generated from accounting objects by surveying the stored accounting objects and copying and aggregating key figures from the accounting object to the financial statement items. The financial statement items form the basis of the financial statements. The copying and aggregating may occur as specified in a plurality of rule sets. To change assignments between the accounting objects and financial statements, it is sufficient to provide a replacement rule set that specifies different copy and aggregation operations.