It was morning in early September and senior investors at Carmignac, the French fund manager, were engaged in a debate that they had been having for months: just how fragile was the world economy? Now, digesting the impact of an August decision by the Chinese authorities to let the value of the renminbi drop only slightly, it was finally time to act.

Carmignac’s €25bn flagship fund Patrimoine held €10bn in equities and the decision was taken to buy insurance against the whole portfolio. They would effectively pull out of the stock market and wait to see what happened.

After a vicious sell-off, markets recovered their poise and in December the US Federal Reserve was sufficiently confident about the outlook to raise interest rates for the first time in almost a decade. But in recent weeks, Carmignac’s decision has looked like the right call: January has been a disaster for stock markets, which have never fallen so far or so fast at the start of a year.