Standard Chartered, the bank leading the $10bn-plus sale of assets in BP, is believed to be behind a $5.25bn (£3.5bn) standby account to protect the crisis-stricken oil giant.
It is understood that the bank gave $2bn to the account when it was set up in May. Credit Suisse, Morgan Stanley, and Goldman Sachs are said to be among those providing the balance.
All four of the banks were subsequently hired to review and sell oil and gas field assets. BP is raising cash to ensure it can cover the potential costs of the Gulf of Mexico oil spill, which has wrecked the FTSE 100 giant's reputation in the US and badly damaged the share price.
At an investor conference last month, BP said it had $15bn available should it have to quickly cover the costs of the spill. This included the standby facility, though BP did not comment on the loan providers. A banker said: "All the banks that lent to BP have ended up with roles in the disposal process."
The news emerged as BP closes in on plugging the oil spill. There have been reports that engineers could end the crisis as soon as tomorrow, more than a month ahead of schedule.
Once the spill has been tackled, pressure on BP's top bosses is expected to be renewed. Investors have been dismayed by the performances of Tony Hayward and Carl-Henric Svanberg, the chief executive and chairman respectively, since the Deepwater Horizon well exploded in April.
Industry sources said that Mr Svanberg is more likely to be replaced than Mr Hayward, who has tried to improve the company's safety record since he took over in 2007.
Standard Chartered and BP spokesmen declined to comment. BP shares closed at 364.8p on Friday, down 0.6 per cent on the start of the day's trading.Reuse content