By Silke Koltrowitz
ZURICH (Reuters) - UBS Chief Executive Oswald Gruebel is not considering stepping down in the wake of the crisis provoked by a London trader suspected of causing a $2 billion loss for the bank, he told Swiss newspaper Der Sonntag on Sunday.
Asked about calls for his resignation that have mainly been expressed by members of Switzerland's Social Democrats, he said: "That is purely political. I am not thinking about stepping down."
He said it was up to the board to decide on this matter.
In the short interview, Gruebel assumed responsibility for all that happens at the bank. "But if you ask me whether I feel guilty, I say no," he said.
"If somebody proceeds with criminal energy, we cannot do anything. That will always exist in our job."
The Sunday Times cited unnamed insiders saying the alleged rogue trader placed bets worth $10 billion before his losses were detected by the bank.
UBS spokesman Serge Steiner declined to comment on the report.
Swiss newspaper NZZ am Sonntag said the UBS board was still supporting Gruebel, who took over as CEO in the middle of the financial crisis and has so far been seen as the man who managed the crisis-shaken bank's turnaround.
Important shareholders such as the Government of Singapore Investment Corp. were still placing their trust in Gruebel, an unnamed member of the UBS board was quoted as saying by the newspaper, adding an alternative person was not in sight.
SonntagsZeitung also quoted an unnamed UBS source saying Gruebel had enough support on the board and among shareholders to push ahead with a restructuring of the investment bank.
Immediate personnel changes at the top were the last thing UBS needed now as they would only destabilize the bank, the manager said, adding Gruebel would present plans for a smaller investment bank at its investor day in November.
Christoph Blocher, vice-president of Switzerland's biggest party, the right-wing People's Party SVP, renewed his calls for a splitting off of the investment bank.
"If the too-big-to-fail proposal passes parliament without this restriction ... one has to seriously examine a ban on investment banking for commercial banks," he said.
NZZ am Sonntag and SonntagsZeitung reported UBS would communicate on Sunday further details on the exact amount of the loss caused by trader Kweku Adoboli.
(Reporting by Silke Koltrowitz; Editing by Daniel Magnowski and David Hulmes)