UBS is facing growing investor pressure to secure SwFr10 billion (£4.9 billion) through a rights issue after the loss-making Swiss investment bank raised SwFr 13 billion from Singapore and Saudi sovereign wealth funds.

Profond, a Swiss pension fund, is pushing for UBS to add a rights issue to a list of proposals that will be voted on at the banks' Annual General Meeting (AGM) set for April 23.

It is understood that Profond is concerned about the SwFr13 billion deal UBS has struck with GIC, a Singapore sovereign wealth fund, and an unnamed Middle Eastern investor.

The new investors will see their debt convert into a 10 per cent holding in UBS, diluting other shareholders' stakes in UBS.

There are also growing fears that UBS could be forced to writedown a further $12 billion (£6 billion) on sub-prime mortgage backed assets.

It would add to the $18 billion write-off the investment bank has already incurred that contributed to its first-ever quarterly loss of SwFr 4.4 billion.

UBS declined to comment on speculation that it needed to raise additional capital, despite securing the cash injection from strategic investors.

A UBS spokesman said: "We have received a request from Profond that we include this as an agenda item.

"We are considering all requests for agenda items at our AGM. We will send out details of those items that will be included on the agenda at the end of March, in a letter to shareholders."

It emerged earlier this month that UBS may be contemplating cutting up to 10 per cent of its workforce, equating to around 8,000 staff, on top of the 1,500 job reduction it has already announced.

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