Jamie Dimon, chairman and chief executive of JP Morgan, said performance in the investment banking business "could have been a bit better" after profits collapsed 70% as the bank was hit by a massive writedown in its fixed income business, becoming the latest victim of the turmoil in the global credit markets.

Profits from the investment bank plunged to $296m (€209m) in the three months to the end of September, down from $976m during the same period last year, with fixed income dragging down better performance in mergers and acquisitions advisory.