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A man is sentenced to 7 years in prison for selling bomb detectors which had no hope of detecting bombs. The contrast with the fate of those who have continued to sell complex mathematical models to both large financial institutions and their regulators over 20 years, which have no hope of protecting them from massive losses at the precise point when they are required, is illuminating.

The devices made by Gary Bolton were simply boxes with handles and antennae. The “black boxes” used by banks and insurers to determine their worst loss in a 1 in 200 probability scenario (the Value at Risk or “VaR” approach) are instead filled with mathematical models primed with rather a lot of assumptions.

The prosecution said Gary Bolton sold his boxes for up to £10,000 each, claiming they could detect explosives. Towers Watson’s RiskAgility (the dominant model in the UK insurance market) by contrast is difficult to price, as it is “bespoke” for each client. However, according to Insurance ERM magazine in October 2011, for Igloo, their other financial modelling platform, “software solutions range from £50,000 to £500,000 but there is no upper limit as you can keep adding to your solution”.

Gary Bolton’s prosecutors claimed that “soldiers, police officers, customs officers and many others put their trust in a device which worked no better than random chance”. Similar things could be said about bankers during 2008 about a device which worked worse the further the financial variables being modelled strayed from the normal distribution.

As he passed sentence, Judge Richard Hone QC described the equipment as “useless” and “dross” and said Bolton had damaged the reputation of British trade abroad. By contrast, despite a brief consideration of alternatives to the VaR approach by the Basel Committee on Banking Supervision in 2012, it remains firmly in place as the statutory measure of solvency for both banks and insurers.

The court was told Bolton knew the devices – which were also alleged to be able to detect drugs, tobacco, ivory and cash – did not work, but continued to supply them to be sold to overseas businesses. In Value at Risk: Any Lessons from the Crash of Long-Term Capital Management (LTCM)? Mete Feridun of Loughborough University in Spring 2005 set out to analyse the failure of the Long Term Capital Management (LTCM) hedge fund in 1998 from a risk management perspective, aiming at deriving implications for the managers of financial institutions and for the regulating authorities. This study concluded that the LTCM’s failure could be attributed primarily to its VaR system, which failed to estimate the fund’s potential risk exposure correctly. Many other studies agreed.

“You were determined to bolster the illusion that the devices worked and you knew there was a spurious science to produce that end,” Judge Hone said to Bolton. This brings to mind the actions of Philippe Jorion, Professor of Finance at the Graduate School of Management at the University of California at Irvine, who, by the winter of 2009 was already proclaiming that “VaR itself was not the culprit, however. Rather it was the way this risk management tool was employed.” He also helpfully pointed out that LTCM were very profitable in 2005 and 2006. He and others have been muddying the waters ever since.

“They had a random detection rate. They were useless.” concluded Judge Hone. Whereas VaR had a protective effect only within what were regarded as “possible” market environments, ie something similar to what had been seen before during relatively calm market conditions. In fact, VaR became less helpful the more people adopted it, as everyone using it ended up with similar trading positions, which they then attempted to exit at the same time. This meant that buyers could not be found when they were needed and the positions of the hapless VaR customers tanked even further.

Gary Bolton’s jurors concluded that, if you sell people a box that tells them they are safe when they are not, it is morally reprehensible. I think I agree with them.

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