Systemic Financial Risk Indicators and Securitised Assets: an Agent-Based Framework

The paper presents an agent-based model of a credit economy which includes a securitisation process and a bailout mechanism for banks' bankruptcies. Within this model's framework banks are able to sell mortgages to a Financial Vehicle Corporation, which finances its activity by creating Mortgage-Backed Securities and selling them to a mutual fund. In turn, the mutual fund collects liquidity by selling shares to households and remunerating them with a monthly interest rate. The impact of this mechanism is analysed by means of computational experiments for different levels of securitisation propensities of banks. Furthermore, we study a set of systemic risk indicators which have the aim to assess financial imbalances within the financial system. Two of them are the mortgage-to-GDP ratio and the Capital Adequacy Ratio which are constructed to detect only the in-balance sheet changes in banks' credit exposure. We consider two additional indicators, similar to the previous ones with the only difference that they are able to account also for the off-balance sheet items. Moreover, we introduce a novel indicator, the so-called VUC indicator, which also targets the off-balance assets. Results confirm that higher securitisation propensities weaken the financial stability of banks with relevant effects on different sectors of the economy. Most important, the analysis of systemic risk reveals the important issue of designing suitable systemic risk indicators for predicting incoming financial crises, finding that an essential feature of these indicators should be to integrate banks' off-balance sheet assets.