Brunswick, a company in the business of bowling alleys and boats, this week became the latest group to refinance its debt with a $250m junk bond offer in a clear sign that the rally in the US high-yield market is still going strong. It is just one of as many as seven or eight deals that JPMorgan is planning to bring out this week. Goldman Sachs lead managed three deals in a single day on Tuesday.

But the market has performed so well that some bankers are starting to fret about the rally reversing.