Finally, short-term yuan-borrowing rates have jumped in Hong Kong in recent days, which could be a sign regulators have decided to intervene to raise the cost of speculating against the yuan offshore.

A weaker yuan could be a big help for China, given that food and energy costs have fallen recently and its exporters are struggling. But the prospect of big capital outflows following an unexpected yuan depreciation, as in 2015, probably still haunts Beijing. Between 2014 and 2016, foreign reserves fell by around $1 trillion.

Oct23: A July research note from Goldman Sachs said yuan usage remains “limited globally, especially relative to the size of China’s GDP and its influence in trade”, and pointed to Beijing’s capital controls as a key limiting factor.