Oswald Grübel, chief executive of Credit Suisse Group, has vowed not to sell Credit Suisse First Boston despite net profits falling 43% in the second quarter as trading revenues tumbled Sfr1.05bn (€682m).

Grübel, sole chief executive since the ousting of John Mack as co-chief executive and head of Credit Suisse First Boston last month after a row over the group's acquisition strategy, said: "We have a performance issue. Compared to our peers our margins are too low and our results are slightly too volatile from quarter to quarter."