By means of a simple economic model, Shleifer and Vishny (1989) describe how top managers can entrench themselves by specific overinvestment. An extension of the model with additional investments exposes interdependencies that exceed the primary value of explanation. The extension of the model focuses on investment behaviour and the impact of the market for corporate control on managerial entrenchment. Despite specific over-investment, total corporate investment does not change. Increased specific investments are balanced by appropriate disinvestments in other areas of the company. Additionally, more competition does not necessarily discipline the manager. In fact, a competitor can increase the divergence between managers and shareholders. An increase in managerial competence on the part of the competitor can even induce a loss of wealth for all actors.