Michael Boss, Helmut Elsinger, Martin Summer, Stefan Thurner

Paper #: 03-10-054

We provide an empirical analysis of the network structure of the Austrian interbank market based on a unique data set of the Oesterreichische Nationalbank (OeNB). We show that the contract size distribution follows a power law over more than 3 decades. By using a novel “dissimilarity” measure we find that the interbank network shows a community structure that exactly mirrors the regional and sectoral organization of the actual Austrian banking system. The degree distribution of the interbank network shows two different power-law exponents that are one-to-one related to two sub-network structures, differing in the degree of hierarchical organization. The banking network moreover shares typical structural features known in numerous complex real world networks: a low clustering coefficient and a relatively short average shortest path length. These empirical findings are in marked contrast to interbank networks that have been analyzed in the theoretical economic and econo-physics literature.