The most well-known contribution to the analysis of contagion through direct linkages in nancial systems is that of Allen and Gale (2000). 2 Using a network structure involving four banks, they demonstrate that the spread of contagion depends crucially on the pattern of interconnectedness between banks. When the network is complete, with all banks having exposures to each other such that the amount of interbank deposits held by any bank is evenly spread over all other banks, the impact of a shock is readily attenuated. Every bank takes a small `hit' and there is no contagion. By contrast, when the network is `incomplete', with banks only having exposures to.
