A fight for greater market share by Saudi Arabia, which has been underpricing its oil against competing for crude from rivals Russia and the United States, also weighed on the market.
West Texas Intermediate (WTI), the New York-traded benchmark for US crude prices, settled down $3.28, or nearly 13 percent, on Friday at $22.63 per barrel.
For the week, the US crude benchmark was down 29 percent. That was WTI’s biggest weekly loss since the week ended 13 January 1991, when it fell 29.5 percent, historical data showed.
Brent, the London-traded global benchmark for crude, settled Friday’s trade down $1.49, or 5 percent, at $26.98. For the week, Brent lost 25 percent.
Oil prices have suffered double-digit losses for four straight weeks now, leaving WTI with a year-to-date loss of 63 percent and Brent with an annual deficit of 59 percent.
The losses came after Saudi Arabia, leader of OPEC, or the Organization of the Petroleum Exporting Countries, failed to reach an agreement with ally Russia for an extension of production cuts beyond March. The Saudis have since cut the selling price of their oil, raised production and embarked on a fight with Russia for greater market share, pulling into the fray the United States.