Credit Suisse CEO Brady Dougan on Thursday said volatility since the start of 2015 has hampered the bank's underwriting and advisory businesses, continuing the tone set in the fourth quarter last year, when volatility sparked by a rapid drop in oil prices boosted trading but hit underwriting activity.

Dougan, in a statement accompanying the Swiss banking group's fourth-quarter and full-year results, said: "Year-to-date profitability of the group is in line with last year. Our private banking and sales and trading businesses have shown an improving trend in recent weeks. Underwriting and advisory activities have started the year more slowly due to market volatility."