»Diversity and Unity of Dominating Influence. A Comparison of Company Group Concepts in Stock Corporation, Group Accounting and Merger Control Law«: The recognition of affiliated companies diverges not only between stock corporation, merger control and group accounting law, but also within these areas of law. At the same time, there is a close connection due to dynamic references or due to legal historical roots. Based on these roots, this paper analyzes the understanding of the respective company group concepts and shows the potential scope for their alignment de lege ferenda as well as their limits.