Many people have experienced the joy of finding some spare change down the back of the sofa. On May 30th the World Bank experienced something similar, if on a grander scale. After rooting around in 176 countries, it discovered almost $7trn in extra global GDP—equivalent to an extra France and a Mexico.

In fact, there may be a better analogy. What the World Bank discovered was not additional money to spend, but the equivalent of a discount voucher, which cuts 4% off the price of every good and service the world buys in a year. That means global spending can stretch further than previously thought.