RBS is not alone in having to shore up its balance sheet
Royal Bank of Scotland shareholders have agreed to buy more than 95% of the shares offered in a £12bn rights issue.
The rights issue is the biggest in UK corporate history, and the firm said investors would take up 5.8bn new shares at a value of 200 pence each.
But shares in RBS ended 5% lower in London at 234 pence.
The bank is not alone in having to ask investors for extra cash after problems in the world credit and US housing markets cut the value of its assets.
Banking sector blues
HBOS and Bradford & Bingley have also asked their investors for extra cash.
Analysts are particularly concerned that HBOS, which was formed by the merger of Bank of Scotland and Halifax, will struggle to raise the £4bn it requires to help restore the bank's finances.
This is because private investors, rather than institutional investors, dominate its share base and are generally less supportive of rights issues.
HBOS's shares ended 7.2% lower, while Barclays shares fell almost 6% on speculation that it would be the next bank to try and sell new shares.
Royal Bank of Scotland (RBS) shares have more than halved in value over the past year - including a 25% slump since the rights issue was announced in April.
Despite a brief rally last week, analysts warned that the bank and its shares may remain under pressure in the coming weeks.
RBS and other banks have suffered from a drop in the value of risky assets, particularly those focused on US sub-prime mortgages.
Sub-prime borrowers are those with poor or non-existent credit histories, and in recent months the number of defaults has jumped.
As a result, many lenders have had to find ways of boosting their cash reserves.
WHAT IS A RIGHTS ISSUE?
Companies issue extra shares to raise money
They are offered to existing shareholders, usually at a discount to the current share price
Shares are offered in proportion to existing holdings, so if you own 10% of the old shares you are offered 10% of the new ones
RBS's circumstances have been exacerbated after it headed a group that bought Dutch lender ABN Amro for 71bn euros last year.
There are about 200,000 RBS shareholders; 93% of the shares are held by major investors, such as pension funds, with the other 7% owned by private individuals.
Shareholders are generally not keen on new share issues because it means that their investments are diluted, the firms' earnings are spread more thinly and each share takes a smaller slice of the company's earnings.
To compensate for these downsides, they are offered the shares at a discount to the market price so they could sell for a quick profit.
"It's a good level of takeup for one of the biggest ever rights issues, done in not easy circumstances," said Alan Beaney, head of investment at Principal Investment Management.
"The company (RBS) is still trading reasonably well and now doesn't have that capital worry so maybe it can be knocked forward now."