Revenues from interest rate and foreign exchange trading have propped up a decline in investment banking revenues this year, according to a new report, as several banks recorded substantial increases in fixed income trading income in the second quarter.

Banks with large interest rate and foreign exchange trading businesses have weathered the downturn in investment banking revenues better than those without, however analysts at Credit Suisse warned, in a report published today, that these profits were unlikely to be repeated over the course of the year.