JPMorgan analysts predict that US corporate borrowers will sell $300bn of debt in the second half, down from $615bn in the first.

Despite strong revenues from rating corporate bond issues in the second quarter, Moody’s officials cautioned that the second half of the year could see a drop in market activity, especially among junk issuers.

Global corporate bond issuance hit a record $1.8 trillion in the first half, according to Standard & Poor's.