Bank Leverage, Financial Fragility and Prudential Regulation

We analyse the determinants of bank balance-sheets and leverage-ratio dynamics, and their role in increasing financial fragility. Our results are twofold. First, we show that there is a value of bank leverage that minimises financial fragility. Second, we show that this value depends on the overall business climate, the expected value of the collateral provided by firms, and the risk-free interest rate. These results lead us to advocate for the establishment of an adjustable leverage ratio depending on economic conditions, rather than the fixed ratio provided for under the new Basel III regulation.