Stress tests of UK banks using a VAR approach

This paper adopts a new approach to stress testing the UK banking system. We attempt to account for the dynamics between banks' write-offs and key macroeconomic variables, through conditioning our stress test on the historical correlation between the variables and allowing for feedback effects from credit risk to the macroeconomy. In contrast to most existing empirical stress testing work, this paper uses a direct measure of banks' fragility - the write-off to loan ratio. We find that both UK banks' total and corporate write-offs are significantly related to deviations of output from potential. Following an adverse output shock, total and corporate write-off ratios increase. Mortgage arrears, on the other hand, appear to be mainly dependent on household income gearing. The results suggest that, even if the most extreme economic stress conditions witnessed over the past two decades were repeated, the UK banking sector should remain robust.