Investment bankers generally start quivering when discussion turns to Thomson Reuters rankings. The quarterly compilation is a leading barometer of the health of the industry and the relative standing of competitors. Even for those less intimately connected with these peculiar institutions, the second-quarter numbers are a good indicator of the health of a significant part of the economic world.

It is significant not because it is big. The $42bn global total of investment banking fees in the first half of 2011 was only 0.1 per cent of the world’s gross domestic product. Even within finance, the business of deals (equity and debt capital markets and mergers and acquisitions) is small: less than 5 per cent of the total US bank and finance business.

The significance comes from the industry's sensitivity. When finance shrinks, the deal trade shrivels – down 60 per cent from the peak in the second quarter of 2007 to the trough in the first quarter of 2009. The industry has had a good recovery – the most recent quarter was two-thirds of the high. The previous euphoric conditions have not returned but sobriety should follow excess. Still, bankers will not be alone in worrying about the most recent trend: the second-quarter total was 16 per cent higher than a year earlier but 20 per cent below the level two quarters ago. Between May and June there was a 72 per cent drop in the issuance of high-yield bonds (hypersensitive instruments).