UBS has confirmed a further 10,000 jobs worldwide are at risk of being axed, causing concern among its 6,500 British investment banking staff.
The Zurich-based bank plans to reduce its headcount from 64,000 to 54,000 by 2015, with some 75% of the losses made outside its base of Switzerland.
A spokesperson for the bank's operation in London told Sky News no exact figure was available for UK losses, but warned it would be fair to assume it would “be in the thousands”.
The restructuring, which involves concentrating the bank’s efforts on advisory, research, equities, foreign exchange and precious metals, is predicted to save £3.5 billion by 2015.
UBS reported a 40% slide in pre-tax operating profits to £1.5bn in the six months to June 30.
Group chief executive Sergio Ermotti said in a statement: "This decision has been a difficult one, particularly in a business such as ours that is all about its people.
"Some reductions will result from natural attrition and we will take whatever measures we can to mitigate the overall effect. Throughout the process we will ensure that our people will be supported and treated with care."
The bank announced the plans as part of its third-quarter results, which revealed a loss of £1.4bn in the three months to September, compared with a profit of £670 million the previous year.
Part of its half-year losses in July were blamed on the nightmarish stock market listing of social networking giant Facebook, which cost UBS £227m.
UBS blamed the loss on the "gross mishandling" of the flotation by Nasdaq, which involved a series of technical errors that caused a delay in the start of trading of Facebook shares in May.
The results arrive at a troubling time for the super banks, as one of its former bankers, Kweku Adoboli, is currently on trial, accused of gambling away money while working for UBS.
Yesterday, Adoboli denied being a rogue trader when he lost the bank £1.4bn.