We examine systemic risk in the interbank market. We first establish that in the German interbank lending market, a few large banks intermediate funding flows between many smaller periphery banks. We then develop a network model in which banks trade off the costs and benefits of link formation. The model is structurally estimated using banks’ preferences as revealed by the observed network structure before the Great Financial Crisis. In out-of-sample tests, model estimates based on pre-crisis data successfully predict changes in the network structure and lending to firms during the Great Financial Crisis. Finally, for each of the intermediaries, we quantify systemic risk and the impact of European Central Bank funding in reducing this risk.

Empirical research on the effect of bank competition on bank risk has so far produced very inconclusive results. In this paper we revisit this long-standing debate and propose a new empirical approach that is concentrated on the relationship between deposit market competition and bank risk. This approach closely follows the traditional theoretical views of the competition and risk relationship and is focused on testing the classical moral hazard problem of the bank: deposit market competition raises the optimal risk choice of the bank by raising the costs of bank liabilities. Since banks can substitute between retail and wholesale funding, we relate deposit market competition to wholesale market conditions and examine their joint effect on the risk of bank assets. The analysis is based on a unique, comprehensive dataset, which combines retail deposit rate data with data on bank characteristics and data on local deposit market features for a sample of 589 US banks. Our results support the notion of a risk-enhancing effect of deposit market competition.