Sergio Ermotti, chief executive of Swiss bank UBS, warned that the volatility seen in 2015 so far is set to continue.
"Volatility for clients is paralyzing the environment (for wealth management)" he said in an interview with CNBC, as the bank announced a third-quarter net profit of 2.1 billion Swiss francs ($2.12 billion), due in large part to a 1.3 billion Swiss franc net tax benefit.
"Extreme volatility, and extreme changes in client sentiment" mean that it is difficult to forecast what will happen this quarter, Ermotti added.
He spoke of the "very challenging environment" of the quarter, including the uncertainty over whether the U.S. Federal Reserve would raise interest rates (it didn't) and volatility in emerging markets.
"I am very happy about how we managed our own risks and clients' risks in the quarter," Ermotti added.
The Swiss lender's net profit figure was up considerably on the same period last year – 762 million Swiss francs – thanks to the tax benefit and a significant foreign exchange charge in the same time in 2014.