USA benchmark West Texas Intermediate (WTI) for delivery in May lost US$1.66 to US$39.79 per barrel, after five sessions spent over the $40 threshold.

Meanwhile, Brent's premium to the WTI crude contract stood at 94 cents a barrel, compared to a gap of 68 cents by close of trade on Wednesday. May Brent crude on London's ICE Futures exchange gave up 30 cents, or 0.7%, to $40.17 a barrel.

Oil prices extended losses Thursday after US supply data a day earlier showed swelling stockpiles and stubbornly high production, further retreating from the $40-a-barrel range and dashing the view of bullish investors banking on the start of a reversal for the world's crude oversupply. Financial markets were broadly risk averse with volumes thin ahead of the Good Friday and Easter break. The increase in imports bloated crude oil stocks. In 2015, production from tight formations-which include, but are not limited to, shale plays-accounted for more than 4 million barrels per day (b/d), or 50% of total USA oil production. The report sent oil prices spiraling during US trading hours.

Thursday's declines were stimulated by a report from the U.S. Energy Information Administration showing a build in domestic crude oil inventories, a sign demand was not yet taking on additional supplies despite continued weakness in the energy market.

Chicago's Population Decreased Significantly in 2015
He added that population growth is generally going to center on urban areas, where employment opportunities are more abundant. Census Bureau, Cook County's population dropped in 2015, marking the area's first decline since 2007.

Much of the rally has been driven by plans engineered by OPEC and other major oil producers to freeze output at January levels.

A stronger greenback tends to hurt demand for dollar-priced commodities, as it makes oil more expensive for buyers using weaker currencies.

The Wall Street Journal reported that oil prices dipped Wednesday on reports of higher inventories in the US.

Those involved in this market have believed the freeze in production from Saudi Arabia and Russian Federation would not have a lasting effect on the crude oil market as the Saudis were technically the only country allowed to adjust the production of crude oil.