The bank's chairman, Marcel Ospel, will step down at the next annual general meeting on April 23.
UBS said it would report SFr12 billion ($12.1 billion) in net losses for the first quarter, and would seek to raise another SFr15 billion from its shareholders through a rights issue.
The bank reported $12 billion in writedowns on US property exposure for the fourth quarter of 2007 and $3.4 billion in the third quarter. It now has $15 billion in remaining subprime exposure and another $16 billion in exposure to Alt-A mortgages. However, it revealed, its holdings of the troubled and illiquid auction rate securities increased from $5.9 billion at the end of 2007 to $11 billion.
UBS said it will hive off most of its US residential exposure into a separate entity, "which will initially be wholly owned and financed by UBS". The bank said this would help it reduce its exposure more efficiently, but did not provide any further details.
Ospel will be replaced by the bank's general counsel, Peter Kurer. Ospel had intended to retire in July 2007, to be replaced by then-chief executive Peter Wuffli, but the bank's board refused to promote Wuffli, who left the bank, and asked Ospel to remain in post. The chief risk officer, Marcel Rohner, was instead promoted to chief executive.
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