"Basically, like in the automotive industry, we want to be 2-3% more efficient every year," he told Swiss newspaper Finanz und Wirtschaft.

With costs of around 17 billion Swiss francs ($18.63 billion), this meant around 400 million francs in annual savings, he said after Credit Suisse announced an overhaul of its investment bank and beat profit forecasts in its results on Thursday.

"We look at where there are duplicates and inefficiencies that can be remedied without compromising," said Gottstein, citing the example of merging the risk and compliance functions.

The rest of the savings would come from other group-wide functions, as well as its business in wealth management, Asia, and reducing the branch network in Switzerland.

"With higher digitisation and automated processes, we can basically get even more out of it. However, we will reinvest all of these savings in the business," said Gottstein, who took over as CEO from Tidjane Thiam in February.

Looking ahead, Gottstein said the bank's M&A business was only seeing a slow pick-up in activity, but he expected high market volatility to continue which was good for the bank's trading business.

"I am also convinced that the capital market will continue to be active. Companies have to refinance themselves, many through capital increases," he told the newspaper.

"And as far as private banking is concerned, we were able to increase sales in the first half of the year by 4% and even currency-adjusted by 7%, which is very solid in this environment. So I'm a little more optimistic here."

($1 = 0.9127 Swiss francs)

(Reporting by John Revill; editing by Jason Neely)