Banking giant Barclays today said Middle Eastern investors were pumping up to £7.3 billion into the business.
The cash injection from Qatari investors and the Abu Dhabi royal family comes as the bank looks to avoid calling on taxpayer funds to strengthen finances weakened by the credit crunch.
The funding move follows an earlier £4.5 billion cash call by the bank in June.
Qatar Holding and Challenger - a wealthy vehicle led by the Qatari royal family - are already investors in the group.
Barclays has also brought on board Sheikh Mansour Bin Zayed Al Nahyan - a member of the Abu Dhabi royal family - as a substantial new investor.
The Middle Eastern trio could end up owning almost a third of the bank when the warrants and notes issued by the bank are converted into ordinary shares.
Barclays said the funding move would allow it to meet the tougher requirements of the Financial Services Authority to help banks withstand financial turmoil.
The cash will boost its core tier one ratio - a key measure of capital strength - to 7.6 per cent, the bank said. It shares rose 8 per cent following the announcement.
Not using public funds to shore up the business also means that Barclays will be able to pay dividends to its shareholders - unlike Royal Bank of Scotland and Halifax Bank of Scotland.
Chief executive John Varley said: "Today's capital raising provides certainty and speed of execution."
In a trading update alongside the capital raising Barclays added that third quarter pre-tax profits were "slightly ahead" of the previous year.
The bank, which bought the US investment banking arm of collapsed Lehman Brothers last month, saw credit market writedowns of £1.2 billion but these were mostly offset by gains elsewhere.
"The financial market environment has continued to be as challenging as any that we have experienced.
"Against this backdrop, we have stayed close to our customers and clients, managed our risks carefully, and taken advantage of opportunities to progress our strategy," Mr Varley added.
The bank chief said the growing presence of Middle Eastern investors reflected the "significant shift" in the availability of capital and economic power over the past five years.
Mr Varley called the move - which has to be approved by shareholders - a "forward-looking and progressive approach to managing the share register".
He said it put Barclays among the strongest banks in the world in capital terms. "We have what we need," he added.
"We think the capital structure works well...we have chosen a route which means we don't have to take advantage of the offer of the Government," Mr Varley said.