Like any good investment theme, the bull case for emerging market infrastructure is simple to spot, harder to actually pin down. The essence is as follows. Surging economic growth has led to higher investment in emerging markets’ infrastructure, with governments splashing out on everything from roads to power plants. This internal spending should help to sustain economic growth, regardless of any weakness in the US.

Does it bear close scrutiny? Spending on infrastructure now makes a bigger contribution to economic output than external trade in many emerging markets. And there are lots of large numbers to throw around. Russia plans to spend $500bn on 20,000km of railways by 2030 – roughly two thirds of the total built during the Soviet period. Brazil is in the middle of a three-year, $250bn project to improve its infrastructure. Saudi Arabia wants to invest $1,000bn over the next 15 years.