4.6.7 Banks’ Behaviour and Misplaced Reliance of Sophisticated Mathematics and Statistics There are many lessons to be learned from the financial crisis. There is a considerable body of opinion that considers that poor risk management lay at the heart of the credit crisis. This lack of awareness of risk exposure is reinforced by Sir John Gieve, who stated when Deputy Governor of the Bank of England, that a weakness in the British banking system “was the failure of the banks and many other investors to appreciate, price and manage risk”. The Bank of England published its analysis of the vulnerabilities of the system in its Financial Stability Reports of 2006 and 2007 (Gieve 2009). It delivered its findings to the CEOs of banks in both London and New York. In particular, it described the banks’ exposure to global imbalances, dependence on wholesale funding and the risk of structured credit markets seizing up in a downturn. However, these executives paid scant regard to the reviews as they took comfort from the sophistication of their risk management systems and hedging strategies and were confident they could ride out the storm. The issue though, as Gieve explained in his speech, was that the banks’ systems were preparing them for a shower, not a hurricane. The predominant assumption of the banks was that the scale and complexity of the securitised credit market had been matched by the evolution of statistically sophisticated and effective techniques for measuring and managing the resulting risks. Central to many of the techniques applied was the concept of value at risk (VaR), enabling mathematical inferences about forward-looking risk (and future price movements) to be drawn from the observation of past patterns of price movement. The financial crisis has revealed, however, severe problems with these techniques. They suggest at the very least the need for significant changes in the waythatVaR-basedmethodologieshavebeenapplied;some,however,posemorefundamental questions about our ability in principle to infer future risk from patterns observed in the past. Four categories of problem have been distinguished in The Turner Review (FSA 2009a), and are described in Chapter 25. A primary message of the financial crisis was that the very complexity of the statistical methods used to measure and manage risk made it increasingly difficult for an analyst to convey the approach adopted and the content of the analysis, and for top management and boardstoassessandexercisejudgementovertherisksbeingtaken.Statisticalandmathematical sophistication ended up not containing risk, but providing false assurance that the emerging risks could be safely ignored.
4.6.7 Banks’ Behaviour and Misplaced Reliance of Sophisticated Mathematics and Statistics There are many lessons to be learned from the financial crisis. There is a considerable body of opinion that considers that poor risk management lay at the heart of the credit crisis. This lack of awareness of risk exposure is reinforced by Sir John Gieve, who stated when Deputy Governor of the Bank of England, that a weakness in the British banking system “was the failure of the banks and many other investors to appreciate, price and manage risk”. The Bank of England published its analysis of the vulnerabilities of the system in its Financial Stability Reports of 2006 and 2007 (Gieve 2009). It delivered its findings to the CEOs of banks in both London and New York. In particular, it described the banks’ exposure to global imbalances, dependence on wholesale funding and the risk of structured credit markets seizing up in a downturn. However, these executives paid scant regard to the reviews as they took comfort from the sophistication of their risk management systems and hedging strategies and were confident they could ride out the storm. The issue though, as Gieve explained in his speech, was that the banks’ systems were preparing them for a shower, not a hurricane. The predominant assumption of the banks was that the scale and complexity of the securitised credit market had been matched by the evolution of statistically sophisticated and effective techniques for measuring and managing the resulting risks. Central to many of the techniques applied was the concept of value at risk (VaR), enabling mathematical inferences about forward-looking risk (and future price movements) to be drawn from the observation of past patterns of price movement. The financial crisis has revealed, however, severe problems with these techniques. They suggest at the very least the need for significant changes in the waythatVaR-basedmethodologieshavebeenapplied;some,however,posemorefundamental questions about our ability in principle to infer future risk from patterns observed in the past. Four categories of problem have been distinguished in The Turner Review (FSA 2009a), and are described in Chapter 25. A primary message of the financial crisis was that the very complexity of the statistical methods used to measure and manage risk made it increasingly difficult for an analyst to convey the approach adopted and the content of the analysis, and for top management and boardstoassessandexercisejudgementovertherisksbeingtaken.Statisticalandmathematical sophistication ended up not containing risk, but providing false assurance that the emerging risks could be safely ignored.
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