Brent crude oil fell $2 to a four-year low under $76 a barrel as traders speculated that Opec was unlikely to cut output to support prices at its meeting yesterday.

Gulf producers Saudi Arabia, Kuwait, Qatar and the United Arab Emirates said they had reached a consensus on oil output policies. Sources said those countries agreed not to press ahead with output cuts.

“The consensus is increasing that they will not provide any significant cut in this meeting,” said Olivier Jakob, oil market analyst at Petromatrix in Zug, Switzerland.

Some fund analysts have said that oil prices could slide to $60 per barrel if Opec does not agree to a significant output cut. Reuters analyst Wang Tao said he expected US oil to drop to $63.85 per barrel over the next four weeks.

Benchmark Brent futures dropped by more $2 to $75.75 a barrel by 0830 GMT, the lowest level since September 2010. US crude also lost more than $1 to a session low of $71.95.

The US Thanksgiving holiday means lower liquidity, and hence the chance of increased volatility, Jakob said.

Another rise in US shale oil production as well as increasing Chinese and US oil stocks boosted available supplies and also weighed on crude values.

Consultancy Energy Aspects said that US crude output averaged 8.86 million barrels per day in September, 1.12 million barrels more than in the same month last year, noting that this was “the fastest monthly growth since April”.

Crude inventories in the United States rose by 1.9 million barrels in the week that ended November 21, according to the US Energy Information Administration, about four times analysts’ expectations for an increase of 467,000 barrels.