Shares in BP fell a further 5% on Tuesday after US President Barack Obama launched his most strident attack yet on the oil giant.
The company - in which most of the UK's pension funds invest - has seen its shares tumble almost 40% since April's oil spill in the Gulf of Mexico.
President Obama said earlier he would have fired BP chief executive Tony Hayward over remarks he made.
Some analysts have called for the BP boss to announce plans to step down.
In an interview with NBC, Mr Obama was asked about comments Mr Hayward made in the wake of the disaster, which killed 11 people, such as "I want my life back" and the Gulf is "a big ocean".
Mr Obama said: "He wouldn't be working for me after any of those statements."
He added he had visited the Louisiana coast "so I know whose ass to kick" and called for dividends due to be paid to shareholders to instead go into a compensation scheme.
The comments have added to the pressure on Mr Hayward's future.
"He should announce he is going to quit as soon as the oil leak had been stopped. That would take some of the pressure off BP," said Hugo Dixon of Reuters Breakingviews.
Mr Hayward was a "liability to the company" and had "become the whipping boy", he told the BBC.
"He has mishandled the communications quite badly."
On Sunday Mr Hayward told the BBC his company was going to stop the leak and take care of the consequences.
"We're going to clean up the oil, we're going to remediate any environmental damage and we are going to return the Gulf coast to the position it was in prior to this event. That's an absolute commitment, we will be there long after the media has gone, making good on our promises," he said.
The oil giant has said the cost of the clean-up operation so far is about $1.25bn.
Oil has been leaking into the Gulf of Mexico since the Deepwater Horizon rig exploded and sank off the coast of the US state of Louisiana on 20 April and has been found on beaches and wetlands along more than 100 miles (161km) of coast from Louisiana to the Florida Panhandle.
A containment cap was lowered over the well last week to siphon off the oil to a containment ship.
At a press conference on Tuesday, BP said it had contained more than 14,800 barrels of oil from the leaking wellhead in the previous 24 hours.
BP is to donate money from selling the oil recovered in the Gulf of Mexico spill to wildlife protection in the region.