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Journal of Banking & Finance Vol. 50 2015

Contagious synchronization and endogenous network formation in financial networks

Christoph Aymanns1,2,3; Co-Pierre Georg4,5

1 University of Oxford · 2 Mathematical Institute of the Slovak Academy of Sciences · 3 New College · 4 University of Cape Town · 5 Deutsche Bundesbank

open access

Abstract

When banks choose similar investment strategies the financial system becomes vulnerable to common shocks. We model a simple financial system in which banks decide about their investment strategy based on a private belief about the state of the world and a social belief formed from observing the actions of peers. Observing a larger group of peers conveys more information and thus leads to a stronger social belief. Extending the standard model of Bayesian updating in social networks, we show that the probability that banks synchronize their investment strategy on a state non-matching action critically depends on the weighting between private and social belief. This effect is alleviated when banks choose their peers endogenously in a network formation process, internalizing the externalities arising from social learning.

DOI
10.1016/j.jbankfin.2014.06.030
Volume
50
Pages
273-285
Language
en
Sources
bibtex:phds-export.bib openalex crossref

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