Seminar paper from the year 2005 in the subject Business economics - Controlling, grade: 1,0, European Business School - International University Schloß Reichartshausen Oestrich-Winkel, language: English, abstract: Questions in the field of group control are increasingly important in today's economic environment. This development is especially driven by the fact that almost 90% of the German public companies and around 50% of the German limited liabilities companies are organized as groups. These structures imply information asymmetries and higher coordination requirements because commonly the parent company is responsible for strategic decisions while the subsidiary is responsible for the operations. As decentralized structures are gaining importance and the complexity of the company's environment is growing, the group control faces new challenges and increasing importance for the management. In its aim to supply rationality assurance to the management it needs to work effective and efficient using a set of control tools. The basic data can be retrieved internally or externally. Especially, in the case of listed subsidiaries the data provided by capital markets seem to be a very simple solution for the problem of information gathering and processing in a complex environment. Hence the following research questions arise: How can a holding control its listed subsidiaries through data from capital markets? What could be rationality deficits and limitation in the application of data from capital markets? Beginning with basic definitions the paper defines management control to lay the basis of the examination and to determine the point of view. The holding is the entity that group control is located in. Capital market data in group control is the theme of this paper and those two terms need to be defined properly. Group control is defined in respect to rationality assurance, so it must be distinguished between external and internal institutions of rationality assurance. The internal institution includes a description of the functions and tasks of the controller. Control instruments are the tools used by the controller to process capital market data in group control. The main part is assessing the theory of the utilization of capital market data in group control. The first step is to ex-amine the aims of the application of capital market data, which are effectiveness and efficiency. In the second step different forms of application of capital market data in group control are assessed by looking at selected control instruments. They are grouped by their employment in the tasks of the controller, which are information, planning and control, and coordination. [...]