BP share price rebounds as analysts say 'buy'

"The headline is obviously negative, but BP will appeal and the appeals process is likely to be dragged out for years," Bernard Hodee, an analyst at Raymond James, told Reuters. The firm kept its rating on BP shares unchanged at "fair value".

The ruling means BP could be liable for penalties of up to $17.6bn under the Clean Water Act, compared with just $3.5bn it has so far set aside for the fines.

Another phase of the trial to determine the penalties is scheduled for January 2015, but BP said it would appeal the ruling, meaning any decision could be years away.

In a note, Citi said: "Although this is now a point of high uncertainty for investors, we believe the financial implications of this ruling will remain significantly below the maximum - the Citi estimate is $8.2bn - a sum that should not impact on BP's ability to fund future growth ambitions nor shareholder dividends."

The 2010 explosion on BP’s Deepwater Horizon oil rig killed 11 men and allowed millions of barrels of oil to flow out of the Macondo well into the Gulf of Mexico.

The incident was ranked as the biggest marine disaster in US history, and wreaked billions of dollars’ of damage to tourism and fishing businesses along the Louisiana coastline.

Under the Clean Water Act, BP faces fines for each barrel of oil spilt. The level of fine depends on the degree of negligence, with maximum penalties of $4,300 per barrel in the worst cases of gross negligence and a maximum of $1,100 per barrel for simple negligence.

more