In accordance with recent Hungarian literature on the two theories on the management of industrial companies (bank rule and managerialism), this paper analyses through a case study the extent and conditions of the banks’ power to enforce interests. The Rimamurány–Salgótarján Ironworks Plc. was one of the biggest Hungarian companies between 1892 and 1914, in which, as contemporaries and earlier literature suggested, banks held financial interest. Latest examinations have proved, however, that the role of banks (in the absence of property and credit) were merely formal. According to the minutes of the board of directors’ meetings, delegates of banks made up 50% of the governing board, but the majority of resolutions were submitted by manager directors, and individual directors had very different roles of influence. The author takes a look at the structure of regular reports by manager directors, then at the separate committee that gave room to the contributions of the other directors, finally at the debates that took place at the meeting and changed the decision. As a result, informal spheres of authority are taking shape: in general, decisions were taken by manager directors, but banker-directors demanded and received thorough information and proved to be active decision- makers in financial questions and matters of banking relations. The article closes by recalling an attempt of takeover: in 1909, two financial investors strove for the shares of a passive company. The lesson of this case emphasizes the existence of divided spheres of authority and illustrates the significance of company investments for banks. In the meantime, fundamental ideas and characteristics of the contemporary stock exchange are being presented.