We analyze the relationship between bank size and risk-taking under the Basel II Capital Accord. Using a model with imperfect competition and moral hazard, we show that the introduction of an internal ratings based (IRB) approach improves upon flat capital requirements if the approach is applied uniformly across banks and if the costs of implementation are not too high. However, the banks’ right to choose between the standardized and the IRB approaches under Basel II gives larger banks a competitive advantage and, due to fiercer competition, pushes smaller banks to take higher risks. This may even lead to higher aggregate risk-taking.

This article discusses the effects of small banks on economic growth. We first theoretically show that small banks operating at a regional level can spur local economic growth. As compared with big interregional banks, small regional banks are more effective in promoting local economic growth, especially in regions with lower initial endowments and severe credit rationing. We then test the model predictions using a sample of German banks and corresponding regional statistics. We find that small regional banks are more important funding providers in regions with low access to finance. The empirical results support the theoretical hypotheses.