BP sheds $26B in market value after rig explosion

BP shares tumbled more than 8 percent Thursday, and the company has lost roughly $25 billion in market value since an offshore rig it hired in the Gulf of Mexico exploded last week and started spewing huge amounts of oil.

Eleven workers are missing and presumed dead following the disaster on the Deepwater Horizon, and a huge oil slick is creeping closer to land. Estimates of the amount of oil gushing from the seabed have risen to 5,000 barrels per day - five times what was originally thought.

BP shares fell Thursday as the situation seemed to be getting worse. Experts said the oil may reach shore by Friday, and President Barack Obama said BP will be responsible to pay for the cleanup.

Transocean Ltd., the oil services company that owned the Horizon, has lost about $4.35 billion in market value since the explosion.

In Thursday trading, BP shares gave up $4.78 to close at $52.56. Transocean lost $6.32, or 7.5 percent, to end at $78.51.