Central bankers do not have to actually spend money – or stop spending it – to move markets. Mario Draghi’s insistence that the European Central Bank would do “whatever it takes” to stabilise the eurozone brought European government bond markets to heel last year and Ben Bernanke’s suggestion that the Federal Reserve could start scaling back its $85bn monthly provision of liquidity has brought volatility back across asset classes.

It is no surprise that US Treasury yields have widened since Bernanke made his remarks on May 22. But Barclays analysts underlined the Fed's global influence when they published research showing that the most correlated market to US quantitative easing is the European high-yield market (see chart).