Ermotti takes the helm at UBS as Grübel quits

Sergio Ermotti, the new boss of UBS, has defended the Swiss bank as one of the "best capitalised" in the world as he attempts to shore up confidence after the $2.3bn (£1.5bn) rogue trading scandal.

The 51-year-old head of UBS's Europe, Middle East and African division was named the interim chief executive of UBS this weekend after the scandal led to the resignation of Oswald Grübel, the banking veteran brought out of retirement to turn the bank around after it was hit by sharp losses during the credit crunch.

After his appointment was announced, Mr Ermotti said: "We are aware that we are facing turbulent times externally and this latest incident is only adding much more necessity for us to react. But let's not forget that UBS is one of the best capitalised banks worldwide."

At the top his agenda is an internal investigation into the scandal, which should be concluded in 10 to 14 days, although external investigations might stop the bank from disclosing its findings. Britain's Financial Services Authority and the Swiss Financial Market Supervisory Authority said they were launching an investigation into the scandal shortly after news of the trading loss broke in mid-September. The bank's board has also asked the new chief to speed up efforts to scale back its investment banking arm as it seeks to protect its core wealth management business.

Mr Ermotti, who joined UBS in April, said the moves would be outlined at a planned investor day in New York in November.

In a memo to staff after his appointment this weekend, Mr Ermotti, writing jointly with the Swiss bank's chairman, Kaspar Villiger, said: "There will be enormous challenges in the coming weeks and months and we are confident that we can realign UBS to deal with the new market environment facing the financial services industry."

Mr Grübel, who was appointed in 2009, said he did not "take the step of resigning lightly". In a message to staff, he added: "I am convinced that it is in the best interests of UBS to approach the future with a new leader at the top."