Financial risk models that underpin market behaviour, economic theory and bank regulation dangerously underestimate the threat to taxpayers and must be completely redrawn to prevent a repeat of the financial crisis, a leading policymaker has warned.
The Bank of England's Andrew Haldane has called for economists to re-think what they mean by "normal"
11:46AM BST 08 Jun 2012
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Andrew Haldane, executive director for financial stability at the Bank of
England, said the crisis provided compelling proof that “catastrophe risk”
has been totally mis-priced. “That was a key fault-line during the crisis
and, as recent experience attests, remains a key fault-line today,” he said
in a paper at the University of Edinburgh Business School.
If taxpayers are to be protected in future, financial regulators must put “in
place robust fail-safes to stop chaos emerging”, such as UK plans to
ringfence banks’ retail operations or US proposals to ban casino-like
proprietary trading.
Such “structural safeguards on worst-case outcomes” need to be accompanied by a massive increase in the “array of financial data available to regulators” provided by banks, he added. The extra information would allow regulators to build a “systemic risk map” not unlike a weather forecast that could “provide early warnings to enable defensive actions to be taken”.
“In a complex, uncertain environment, the only fail-safe way of protecting against systemic collapse is to act on the structure of the overall system, rather than the behaviour of each individual within it,” he said. “Until then, normal service is unlikely to resume.”
In a wide-ranging piece of research that sourced evidence not just from economics but from physics, biology and even behaviour on Twitter, Mr Haldane argued that the orthodox models used to measure risk overstate “normality” and underestimate the costs and probability of “catastrophe”.
To make the financial system safer, they need to be torn up, he said in the
paper, co-authored with Bank economist Benjamin Nelson.
“The economics profession has for much of the 20th century been bewitched by normality. Real business cycle theory in economics and efficient markets theory in finance bear the tell-tale signs of this intellectual infatuation,” he said. “Over the past five years, the real world has behaved in ways which make a monkey of these theories.”
Changing the dangerous consensus “will require a fairly fundamental re-think of the foundations of modern-day economics, finance and econometrics”, Mr Haldane added.
Popular models that underpin banks’ risk management, such as Value-at-Risk (VaR), Black-Scholes and Vasicek, underprepare directors and regulators for a “fat tail”, or catastrophe event.
Citing studies of actuarial models used in insurance, Mr Haldane said “fat tails... would be expected to occur approximately once every 800 years for GDP and once every 64 years for equities”. “In reality, for GDP it appears to occur roughly once every century, for equities once every eight years.”
Regulatory risk measurements using the Vasicek model underestimate capital requirements by between 20pc and 85pc compared with a proper analysis of the past three centuries, he added. He cited JP Morgan’s recent $2bn trading loss as an example of the failure of VaR.
Changing the accepted wisdom on how to calculate risk is more important now than ever before, he added. “As the world becomes increasingly integrated – financially, economically, socially – interactions among the moving parts may make for potentially fatter tails. Catastrophe risk may be on the rise."
“The economics profession has for much of the 20th century been bewitched by normality. Real business cycle theory in economics and efficient markets theory in finance bear the tell-tale signs of this intellectual infatuation,” he said. “Over the past five years, the real world has behaved in ways which make a monkey of these theories.”
Changing the dangerous consensus “will require a fairly fundamental re-think of the foundations of modern-day economics, finance and econometrics”, Mr Haldane added.
Popular models that underpin banks’ risk management, such as Value-at-Risk (VaR), Black-Scholes and Vasicek, underprepare directors and regulators for a “fat tail”, or catastrophe event.
Citing studies of actuarial models used in insurance, Mr Haldane said “fat tails... would be expected to occur approximately once every 800 years for GDP and once every 64 years for equities”. “In reality, for GDP it appears to occur roughly once every century, for equities once every eight years.”
Regulatory risk measurements using the Vasicek model underestimate capital requirements by between 20pc and 85pc compared with a proper analysis of the past three centuries, he added. He cited JP Morgan’s recent $2bn trading loss as an example of the failure of VaR.
Changing the accepted wisdom on how to calculate risk is more important now than ever before, he added. “As the world becomes increasingly integrated – financially, economically, socially – interactions among the moving parts may make for potentially fatter tails. Catastrophe risk may be on the rise."