The Royal Bank of Scotland is to ask its shareholders for £10 billion, it has been reported.
With a cash shortage following the global credit crunch, the lender will raise money in what is reported to be the biggest rights issues in UK corporate history.
BBC business editor, Robert Peston, said he understood it would go ahead next week.
Liberal Democrat treasury spokesman, Vince Cable supported the idea: "It’s positive and it’s necessary and it’s got to happen for all of the big banks," he told the BBC.
RBS has made a number of acquisitions, including the purchase of Dutch bank ABN Amro and it now has little remaining cash.
It is thought that other financial institutions in similar positions may also look to their shareholders for cash.
RBS owns other lenders, including NatWest and Ulster Bank, and is the second largest bank in the UK.
Citigroup, the world’s biggest bank has announced it will lose 9,000 jobs and reported losses of $5.1 billion (£2.5 billion).