Risk Trading, Network Topology, and Banking Regulation

In the context of understanding the nature of the risk-transformation process of the financial system we propose an iterative risk-trading game between several agents who build their trading strategies based on a general utility setting. The game is studied numerically for different network topologies. Consequences of topology are shown for the wealth time series of agents, for the safety and efficiency of various types of networks. The proposed setup allows a stringent analysis of the effects of different approaches to banking regulation as currently suggested by the Basle Committee of Banking Supervision. We find a phase transitionlike phenomenon, where the Basle parameter plays the role of temperature and system safety serves as the order parameter. This result suggests the existence of an optimal regulation parameter. As a consequence a tightening of the current regulatory framework does not necessarily lead to an improvement of the safety of the banking system. Moreover, the potential impact of catastrophic events on the financial system can be measured within this framework.