That complexity externality is currently largely unrecognised and un-priced by regulatory rules. Indeed, under the current Basel rules intra-financial system exposures carry a much lower capital charge than exposures outside the financial sector. 26 From a system-wide complexity perspective, this may be the wrong relative risk-ranking. (e)  Structural change  Over the past 30 years or so, the regulatory direction of travel has been towards pricing risk in the financial system, rather than prohibiting or restricting it. In the language of Weitzman, regulators have pursued price over quantity-based regulation (Weitzman (1974)). That makes sense when optimising in a risky world. It may make less sense when optimising in an uncertain world. Quantity-based restrictions may be more robust to mis-calibration. Simple, quantity-based restrictions are the equivalent of a regulatory commandment: “Thou shalt not”. These are likely to be less fallible than: “Thou shalt provided the internal model is correct”. That is one reason why Glass-Steagall lasted for 60 years longer than Basel II. Quantity-based regulatory solutions have gained currency during the course of the crisis. In the US, the Volcker rule is a quantity-based regulatory commandment: “Thou shalt not engage in proprietary trading”. In the UK, the Independent (“Vickers”) Commission on Banking has also proposed structural, quantity-based reforms: “Thou shalt not co-mingle retail deposit-taking and investment banking”. Yet even these notionally simple, structural proposals run some risk of backdoor complexity. For example, the consultation document accompanying Volcker already runs to 298 pages.

Like disease detection, frisbee catching, sports prediction and stock-picking, living a moral life is a complex task. The Ten Commandments are heuristics to help guide people through that moral maze, the ultimate simple rules. They have proven remarkably robust through the millennia. Less has been more. (3)  Finance – more is more? The response to the financial crisis by banks and regulators has been swift and sizeable. Gaps in risk management have been filled, deficiencies in regulation plugged, errors by regulators corrected. This is a self-healing and familiar response. Past crises have also been met by a combination of more risk management, more regulation and more regulators. More has been more. (a)  The Tower of Basel  The foundations for today’s financial regulatory framework were laid in the 1980s. The Basel Accord of 1988 was a landmark. It was the first-ever genuinely international prudential regulatory agreement. For the first time in financial history, a minimum standard had been established for all internationally-active banks. Yet despite its breadth, the Basel I agreement was only 30 pages long. 8 This brevity came courtesy of focussing on a limited set of credit risks measured at a broad asset class, rather than individual exposure, level. Only five different risk weights were defined under Basel I, varying from zero to 100%. Calculating regulatory capital ratios was possible using pad and pen. In taking this simplified approach, the Basel Committee fully recognised its limitations. It was recognised that the role of regulatory rules was not to capture every raindrop.