Updated from 10:53 a.m. with additional fine information and stock price.
NEW YORK (TheStreet) -- Shares of BP (BP) fell -6.01% to $44.85 in afternoon trading Thursday after a federal judge ruled the oil company acted with gross negligence in the Gulf of Mexico oil spill in 2010.
The decision could force BP to pay up to $18 billion in additional fines and penalties to the government, according to Bloomberg. The London-based company has already paid $28 billion since the incident occurred.
"BP's conduct was reckless," U.S. District Judge Carl Barbier wrote in a decision in New Orleans federal court on Thursday. "Transocean's (RIG) conduct was negligent. Halliburton's (HAL) conduct was negligent."
Must Read: Hasn't BP Suffered Enough?
Barbier placed 67% of the blame with BP, 30% with Transocean and 3% with Halliburton.
The oil company also reduced its daily production target in Iraq's largest oil field. The company signed a deal with the Iraqi government to trim the target at Rumaila but extended its output for five years.
BP now expects production to hit 2.1 million barrels a day in the next 10 years, which is approximately 800,000 barrels more than the current output, the company'said. That figure is less than the company's previous mark of 2.85 million barrels a day.
Separately, TheStreet Ratings team rates BP PLC as a "buy" with a ratings score of B-. TheStreet Ratings Team has this to say about their recommendation: