UBS is standing by its third-quarter pre-tax loss estimate of up to Sfr800m (€478m) as it gears up to open the reporting season for Europe's biggest banks tomorrow, after a Swiss media report suggested the sub-prime crisis could spark bigger-than-expected trading writedowns at the bank.

UBS warned on October 1 that writedowns in its fixed income, rates and currencies, mainly on the sub-prime front, would drive the group to a pre-tax loss of between Sfr600m and Sfr800m in the third quarter, its first quarterly loss in nine years. The bank reconfirmed that range today, barely 24 hours before it releases the keenly awaited quarterly figures.