Regulatory and 'Economic' Solvency Standards for Internationally Active Banks
Bank of England Working Paper No. 161
34 Pages Posted: 24 Nov 2003
Date Written: August 2002
One of the most important policy issues for financial authorities is to decide at what level average capital charges should be set. The decision may alternatively be expressed as the choice of an appropriate survival probability for representative banks over a horizon such as a year, often termed a 'solvency standard'. This article sheds light on the solvency standards implied by current and possible future G10 bank regulation and on the 'economic solvency standard' that banks choose themselves by their own capital-setting decisions. In particular, we employ a credit risk model to show that the survival probability implied by the 1988 Basel Accord is between 99.0% and 99.9%. We then demonstrate that if a new Basel Accord were calibrated to such a standard, it would not represent a binding constraint on banks' current operations since most banks employ a solvency standard significantly higher than 99.9%. To show this, we employ a statistical analysis of bank ratings adjusted for the impact of official or other support as well as credit risk model calculations. Lastly, we advance a possible explanation for the conservative capital choices made by banks by showing that swap volumes are highly correlated with credit quality for given bank size. This suggests that banks' access to important credit markets like the swap markets may provide a significant discipline in the choice of solvency standard.
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