% WARNING: This file may contain UTF-8 (unicode) characters. % While non-8-bit characters are officially unsupported in BibTeX, you % can use them with the biber backend of biblatex % usepackage[backend=biber]{biblatex} @techreport{NBERw15611, title = "Liaisons Dangereuses: Increasing Connectivity, Risk Sharing, and Systemic Risk", author = "Battiston, Stefano and Gatti, Domenico Delli and Gallegati, Mauro and Greenwald, Bruce C and Stiglitz, Joseph E", institution = "National Bureau of Economic Research", type = "Working Paper", series = "Working Paper Series", number = "15611", year = "2009", month = "January", doi = {10.3386/w15611}, URL = "http://www.nber.org/papers/w15611", abstract = {We characterize the evolution over time of a network of credit relations among financial agents as a system of coupled stochastic processes. Each process describes the dynamics of individual financial robustness, while the coupling results from a network of liabilities among agents. The average level of risk diversification of the agents coincides with the density of links in the network. In addition to a process of diffusion of financial distress, we also consider a discrete process of default cascade, due to the re-evaluation of agents' assets. In this framework we investigate the probability of individual defaults as well as the probability of systemic default as a function of the network density. While it is usually thought that diversification of risk always leads to a more stable financial system, in our model a tension emerges between individual risk and systemic risk. As the number of counterparties in the credit network increases beyond a certain value, the default probability, both individual and systemic, starts to increase. This tension originates from the fact that agents are subject to a financial accelerator mechanism. In other words, individual financial fragility feeding back on itself may amplify the effect of an initial shock and lead to a full fledged systemic crisis. The results offer a simple possible explanation for the endogenous emergence of systemic risk in a credit network.}, }