The size distribution of the banking sector and the effects of monetary policy

In recent years, the industrial organization of the banking system has received a large amount of attention. In particular, it is generally viewed that the size distribution of the banking sector has changed where it is dominated by a small number of large institutions. In this paper, we develop a model of imperfectly competitive banks that differ in terms of the size of their deposit base. Such differences are important for aggregate credit market activity and the effects of monetary policy. Notably, we explain how the optimal size distribution of the banking system involves trade-offs from distortions in credit markets due to imperfect competition across banking markets. Second, the effects of monetary policy on credit market activity are weaker in an economy dominated by a small number of large banks. Empirical analysis examining the role of concentration among the current members of the European Monetary Union is consistent with the predictions of the model.