Shares in BP fell a further 4.2% on Wednesday amid fears that it will cut its dividend to help pay for the Gulf of Mexico disaster.
The company's market value has now tumbled by almost 40% since April's oil spill.
Before the disaster, they were trading at 648p, but ended Wednesday's session at 391.5p.
The sharp fall in BP's share price is bad news for UK pension funds, which invest heavily in the firm.
The oil company has claimed that it pays £1 in every £7 of dividends that the pension funds receive from FTSE 100 companies.
Wednesday's losses followed BP shares sliding 5% on Tuesday after US President Barack Obama said he would have fired chief executive Tony Hayward over remarks he made.
Mr Hayward made comments such as "I want my life back" and called the Gulf "a big ocean" in the wake of the disaster, which killed 11 people.