The Trouble With Financial Bubbles

LONDON – Very soon after the magnitude of the 2008 financial crisis became clear, a lively debate began about whether central banks and regulators could – and should – have done more to head it off. The traditional view, notably shared by former US Federal Reserve Chairman Alan Greenspan, is that any attempt to prick financial bubbles in advance is doomed to failure. The most central banks can do is to clean up the mess.

Bubble-pricking may indeed choke off growth unnecessarily – and at high social cost. But there is a counter-argument. Economists at the Bank for International Settlements (BIS) have maintained that the costs of the crisis were so large, and the cleanup so long, that we should surely now look for ways to act pre-emptively when we again see a dangerous build-up of liquidity and credit.

Hence the fierce (albeit arcane and polite) dispute between the two sides at the International Monetary Fund’s recent meeting in Lima, Peru. For the literary-minded, it was reminiscent of Jonathan Swift’s Gulliver’s Travels. Gulliver finds himself caught in a war between two tribes, one of which believes that a boiled egg should always be opened at the narrow end, while the other is fervent in its view that a spoon fits better into the bigger, rounded end.

It is fair to say that the debate has moved on a little since 2008. Most important, macroprudential regulation has been added to policymakers’ toolkit: simply put, it makes sense to vary banks’ capital requirements according to the financial cycle. When credit expansion is rapid, it may be appropriate to increase banks’ capital requirements as a hedge against the heightened risk of a subsequent contraction. This increase would be above what microprudential supervision – assessing the risks to individual institutions – might dictate. In this way, the new Basel rules allow for requiring banks to maintain a so-called countercyclical buffer of extra capital.