Grenzplankostenrechnung (GPK) is a German costing methodology, developed in the late 1940s and 1950s, designed to provide a consistent and accurate application of how managerial costs are calculated and assigned to a product or service. The term Grenzplankostenrechnung, often referred to as GPK, has been translated as either Marginal Planned Cost Accounting or Flexible Analytic Cost Planning and Accounting. The GPK methodology has become the standard for cost accounting in Germany as a "result of the modern, strong controlling culture in German corporations". German firms that use GPK methodology include Deutsche Telekom, Daimler AG, Porsche AG, Deutsche Bank, and Deutsche Post (German Post Office). These companies have integrated their costing information systems based on ERP (Enterprise Resource Planning) software (e.g., SAP) and they tend to reside in industries with highly complex processes. However, GPK is not exclusive to highly complex organizations; GPK is also applied to less complex businesses. GPK's objective is to provide meaningful insight and analysis of accounting information that benefits internal users, such as controllers, project managers, plant managers, versus other traditional costing systems that primarily focus on analyzing the firm's profitability from an external reporting perspective complying with financial standards (i.e., IFRS/FASB), and/or regulatory bodies' demands such as the Securities and Exchange Commission (SEC) or the Internal Revenue Services (IRS) taxation agency. Thus, the GPK marginal system unites and addresses the needs of both financial and managerial accounting functionality and costing requirements. Resource Consumption Accounting (RCA) is based, among others, on key principles of German managerial accounting that are found in GPK. Background The origins of GPK are credited to Hans-Georg Plaut, an automotive engineer and Wolfgang Kilger, an academic, working towards the mutual goal of identifying and delivering a sustained methodology designed to correct and enhance cost accounting information. Plaut concentrated on the practical elements of GPK, while Kilger provided the academic discipline and GPK documentation that is still being published in cost accounting textbooks taught in German-speaking universities. The primary textbook on GPK is Flexible Plankostenrechnung und Deckungsbeitragsrechnung. In 1946, Plaut founded an independent consulting business in Hannover, Germany which continued to grow employing more than 2,000 consultants. Plaut and Kilger focused on creating a cost accounting system that would cater to managers who are responsible for controlling costs, managing profits and providing information that would enable managers to make informed decisions. Concepts of GPK GPK is a marginal costing system and is decidedly