What was the root cause of the financial crisis? Ask any economist or banker and undoubtedly they will at some point mention leverage (see e.g. here, here and here). Yet when a capital requirement based on leverage — the leverage ratio requirement — was introduced, fierce criticism followed (see e.g. here and here). Drawing on the insights from a working paper, and thinking about the main criticism — that a leverage ratio requirement could cause excessive risk-taking — this seems not to have been the case.
The leverage ratio requires banks to hold capital in proportion to the overall size of their balance sheet. As opposed to the capital ratio, risk-weights are irrelevant to its calculation. The leverage ratio therefore makes it relatively more costly for banks to engage in low margin activities. One such activity – which is crucial to the transmission of monetary policy and financial stability – is repo. This column shows that a tightening of the leverage ratio resulting from a change in reporting requirements incentivised UK dealers to reduce their repo activity, especially affecting small banks and non-bank financial institutions. The UK gilt repo market, however, showed resilience with foreign, non-constrained dealers quickly stepping in.
A key feature of the post-crisis regulatory reform agenda has been the introduction of a leverage ratio to complement the risk-weighted framework. The FPC designed the UK leverage ratio to mirror risk-weighted capital requirements so the two frameworks move in lock-step over time and across firms. For the sake of simplicity however, the FPC did not reflect Pillar 2 capital charges, which aim to capture risks that cannot be modelled adequately in the risk-weighted framework, in the leverage ratio framework. In this post we explore what happens to leverage and risk-weighted requirements once Pillar 2 are taken into account. We find that in keeping the leverage ratio simple, the perfect lock-step interaction with risk-weighted requirements no longer holds, which could prompt riskier banks to take on more risk.
When banks are subject to both a leverage and a risk-weighted constraint they may violate a fundamental law of economics: that of demand. In our theoretical model, some banks constrained by the leverage ratio react to an increase in capital requirements by investing more in the asset. This so-called ‘Giffen’ behaviour is very counterintuitive. One would assume the opposite to be the case: higher capital requirements should discourage lending. In our theoretical model, Giffen behaviour is likely to occur for firms that hold predominantly low-risk weighted asset and are therefore bound by the leverage ratio. The real-world equivalent in the context of mortgages would be building societies and, in the future, ring-fenced banks. Continue reading “Are mortgages like potatoes? Unintended consequences in a world of many constraints”→