The markets' willingness to take central banks at their word is "somewhat surprising", in the eyes of Guy Debelle, who is sceptical that forward guidance is responsible for the "prolonged period" of low volatility across the globe.

Debelle, a Reserve Bank of Australia assistant governor, told an audience in Sydney that financial markets "have been quiet, maybe too quiet" for much of the year.

"One popular argument for stability is that the low volatility reflects the forward guidance of central