In the global rout of financials, have exchanges been unfairly picked on? After rising about 70 per cent in 2007 on the back of record trading volumes, the Dow Jones Global Exchanges index has lost 15 per cent of its value already this year, in spite of a recent rally. So unforgiving is the mood of investors that when Deutsche Börse announced a tax break that would enhance this year’s earnings by an estimated 10 per cent, its shares barely budged.

The aversion looks overdone. Unlike brokers and fund managers, exchanges offer solidity in slowing economies – oodles of cash, high barriers to entry, and resilient top lines. Analysis of the past 30 years by Citigroup shows that volumes in cash equities on the New York Stock Exchange actually increased during recessionary periods. Only after a serious market event – the crash of October 1987 – did volumes slip more than a couple of per cent. Futures on the Chicago Mercantile Exchange followed a similar pattern.