Does an inverted yield curve matter? Stock traders think it does, at least on the evidence of this week’s thin trading in Wall Street. Whether they are right to be worried to the tune of selling the Dow Jones Industrial Average down by more than 100 points, as happened on Tuesday, is another matter.

The yield curve is a fundamental measure of the government bond market, and looks at how the yields on bonds vary according to their duration. Normally, the curve slopes upwards, with long-dated bonds yielding more than short-dated bonds.