Ex-chairman: UBS chairman must step down in May

UBS Chairman Kaspar Villiger, who heads the Swiss banking giant recently shaken by a rogue trading scandal, should step down in May, the bank\'s honorary chairman said on Sunday. Under the current succession plan, Axel Weber is set to replace Villiger as UBS chairman in 2013. \"It would be good if he ceded the chairmanship at the next general assembly in May to his designated successor,\" honourary chairman Niklaus Senn told the SonntagsZeitung newspaper on Sunday. \"Weber is an internationally known banker...In my opinion, the definitive solution to the succession should be set during the next general assembly,\" added Senn, 85, who previously served as UBS\'s chairman. Weber has already been been given a mandate to find a permanent replacement for departed CEO Oswald Gruebel, who resigned on September 24 after details of the 1.7 billion euro ($2.4 billion) fraud emerged. Sergio Ermotti was appointed interim CEO after Gruebel stepped down to take responsibility for the alleged rogue trading of Kweku Adoboli who has been charged by British police with fraud. UBS said at the time it would \"fully support\" an independent investigation into the rogue trading and would ensure that \"mitigating measures\" were implemented to prevent such incidents from recurring. Ermotti told SonntagsBlick newspaper the UBS must prevent a similar scandal as it could threaten the future of the bank and Switzerland as a whole. The Fitch ratings agency on Thursday downgraded UBS one notch on the basis that Fitch no longer believes the Swiss government is an absolute guarantor of its stability.