The group said results were "likely to be at or slightly below break-even" after further write-downs on investments hit by the credit crunch.

The figures would have been worse if not for a 3 billion Swiss franc (£1.5bn) tax break on its losses to date. The group has written off more than £19bn since the crisis began last summer.

Although the group's asset management and wealth management divisions performed well, "further market deterioration" led to more losses in the UBS investment banking operation.

UBS has paid dearly for its exposure to complex investments linked to the crisis-hit US sub-prime mortgage market.

In May the group announced plans to cut 5,500 jobs. Like many major banking groups this year, the firm has moved to shore up its finances by calling on investors for nearly £8bn in a rights issue, as well as selling off businesses.

It has also raised cash from overseas sovereign wealth funds, which last week pumped £4.5bn into Barclays.

Zurich-based UBS looked to assure investors yesterday that it "has no need to raise new equity" following the fund-raising exercise.

Its 'tier-one ratio' – the proportion of shareholder funds to its risk-weighed assets and essentially a measure of how well-capitalised a bank is – is 11.5 per cent.

Since being hit by the crunch, UBS has also unveiled a corporate overhaul aimed at tightening up board supervision and clamping down on risk-taking within the business. Four members of the group's board are stepping down.