U.S. crude prices jumped as much as 13 percent on Friday after a report once again suggested OPEC might finally agree to cut production to reduce the world glut, while a bounce in stock markets fed appetite for risk.
Despite the strong daily gain, oil prices were poised to end the week down with significant losses. But U.S. oil settled up more than 12 percent, for the best one-day gain since February 2009, when WTI gained 14.04 percent.
The about-turn came after one of the most volatile weeks for oil, with prices initially falling nearly 14 percent over a four-day stretch before springing back higher.
The United Arab Emirates' energy minister said the Organization of the Petroleum Exporting Countries was willing to cooperate on an output cut, the Wall Street Journal reported after Thursday's settlement in U.S. futures. He also said cheap oil was forcing supply reductions that would help rebalance the market.
The UAE's comments, coming after vain efforts earlier in the week by Venezuela and Russia to stir Saudi Arabia and other major producers into agreeing to output cuts, was initially greeted with skepticism by many traders.