The first serious post-war banking crisis came after the collapse of the Bretton Woods semi-fixed exchange rate system and an acceleration in the deregulation of banking. That precipitated a liquidity explosion and property market boom, which culminated in a banking crisis in the UK in 1973, along with a rather less severe one in the US. These difficulties were compounded by currency losses, which sank the Herstatt Bank in Germany and Franklin National Bank in the US.

The Latin American debt crisis followed in 1982 when Mexico announced it was unable to service its debt. Then there was trouble in 1990 when banks in the US, Europe and Japan were hit by another property plunge. After that came the Asian crisis in 1997, followed 10 years later by the biggest episode of collective memory loss in banking since the 1930s. On that basis, with a little rounding up, we could say that bankers have on average a nine-year itch.

This lag makes intuitive sense since bankers' risk appetites are inevitably dulled by the searing experience of the crisis and the regulatory backlash that it spawns. It also takes time to rebuild balance sheets that are weighed down by bad debts, especially when regulators accept that the capital base is too slender to permit timely recognition of losses. That said, the interesting question is what changes have taken place in finance that might shorten the itch. One that stands out is the extraordinary speed with which banking psychology has returned to business as normal this time, despite the overwhelming nature of the crisis.

David Fuller's view For prudent investors, it is probably best to assume that a banking sector will go bust - somewhere - at least every nine years. If we accept this, it will be easier to keep our eyes open for warning signs.

One will be a superior stock market performance during which the capitalisation weighting of the banking sector increases significantly for a number of years. Crucially, however, relative strength usually wanes before the broader stock market index. For instance, the S&P 500 Banks Index last peaked in February 2007. The S&P 500 Index did not peak until October 2007. Another clue is that conspicuous consumption will be notable among bubble bankers. Lastly, an overwhelming majority of business school students in the bubble territory will aspire to be investment bankers.

The 2008 blow-up in Western banks was exceptional, even for bankers. That will keep regulators on their toes and restrain bankers, at least for a while. We should have at least three to four more years before the next banking sector crisis occurs somewhere. Enjoy the lull.