A former chief executive Luqman Arnold has called on Switzerland's biggest bank, UBS, to split off its investment banking unit.
The move, he says, would help counter the effects of massive losses incurred in the United States subprime crisis. The investor has also demanded a shake-up of the bank's governance, and the removal of the newly appointed chairman.
Arnold's proposal came after UBS announced writedowns totalling more than SFr40 billion ($39.7 billion) for the past nine months.
Critics have blamed the investment bank arm for convincing the traditionally conservative bank to move into trading high-risk mortgage securities. UBS results have suffered they say because the bank has stuck with an integrated model, which offsets the losses in one unit with profits from others.
A UBS spokesman said the bank would respond to a letter from Arnold. His Olivant investment company owns 0.7 per cent of the bank, making it one of its biggest shareholders.
Arnold was dismissed as CEO of UBS in 2001 after just eight months in the job and a reported power struggle with the bank's board and its chairman, Marcel Ospel.
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