Modelling the liquidity ratio as macroprudential instrument

The Basel 3 Liquidity Coverage Ratio (LCR) is a micro prudential instrument to strengthen the liquidity position of banks. However if in extreme scenarios the LCR becomes a binding constraint, the interaction of bank behaviour with the regulatory rule can have negative externalities. We simulate the systemic implications of the LCR by a liquidity stress-testing model, which takes into account the impact of bank reactions on second round feedback effects. We show that a flexible approach of the LCR, in particular one which recognises less liquid assets in the buffer, is a useful macroprudential instrument to mitigate its adverse side-effects during times of stress. At extreme stress levels the instrument becomes ineffective and the lender of last resort has to underpin the stability of the system.