The Royal Bank of Scotland (RBS) has said it is planning to cut 3,500 jobs, with most of them to happen this year.
The cuts are part of a reorganisation and shrinkage of its investment bank.
The losses, which will be split between its UK and international offices, come on top of 2,000 cuts announced earlier.
Its "wholesale banking" business, which provides services to large clients including investment banking services, will be split into separate "markets" and "international banking" divisions.
The markets division - which comprises RBS' main trading activities - will focus on the bank's traditional strengths of debt, currency and money markets.
The wholesale banking division will provide services for the bank's biggest clients.
These will include corporate advisory services transferred from its investment bank - such as helping major companies borrow money by issuing bonds - as well as cash management and payments services.
The bank said that it planned to close or sell off other business lines, such as those dealing with shares and stock markets, as well as its business advising companies on mergers and acquisitions.
It is also looking to dispose of its corporate brokerage, Hoare Govett.
These business lines were ones that had been added or expanded only in recent years under the leadership of former chief executive Sir Fred Goodwin.
RBS also said in its statement that the size of the balance sheet - the total loans and investments - of its former investment banking division would be reduced by more than a quarter, from £420bn to £300bn, over three years.
This will enable it to cut its borrowing from wholesale money markets - which evaporated during the 2008 financial crisis, threatening the bank's collapse - by £75bn.
RBS said the restructuring was also designed to prepare the bank for new UK regulatory requirements for banks to ring-fence their core UK operations from their riskier investment banking activities.
The bank's dealings with British small and medium-sized companies will accordingly be transferred away from the new international banking division, and handled via its UK banks.
There was no mention of any specific downscaling of its international operations.
However, there has been speculation that its operations in the Irish Republic - including Ulster Bank, which RBS bought in 2000 - and in Australia may be affected
Chancellor George Osborne announced the change in strategy at the bank in December 2011.
"Investment banking will continue to support RBS's corporate lending business but RBS will make further significant reductions in the investment bank, scaling back riskier activities that are heavy users of capital or funding," Mr Osborne told Parliament in December.
Mr Osborne's announcement came in the wake of a report into the bank by the Financial Services Authority in December 2011 which pointed to "errors of judgement and execution" by RBS management which led to its failure in 2008.
The bank is now 84%-owned by the UK government after taxpayers injected £45.5bn of new capital into RBS.