Imagine tourists piling on to a holiday island in droves, only to want out again fast on rumours of an approaching typhoon. They rush to the airport to find only a few small propeller-driven aircraft on hand. The result would be a huge and anxious queue in departures.

That is an apt analogy for where the bond market has been heading since the financial crisis. A rush by governments and companies to take advantage of record low interest rates has boosted bond market issuance, while new regulations have reduced banks' ability to warehouse risk.