Systemically Important Accounts, Network Topology and Contagion in Artis

This study investigates the relevance of network topology for the stability of payment systems in the face of operational shocks. The analysis is based on a large number of simulations of the Austrian large-value payment system ARTIS that quantify the contagion impact of operational shocks at participants’ sites. It uncovers that only few accounts are systemically important. We also find that network indicators at the node level can have some explanatory power, which is higher when the analysis focuses on contagion measured by the number of banks with unsettled payments than on that measured by the value of unsettled payments. The explanatory power is, however, lower than that of the more traditional measures of node activity(value and volume) of payments. At this stage of our research, network indicators at the network level seem to be of limited use for stability analysis.