Oil prices fell on Wednesday as ample supply pressured futures even as the prospect of economic stimulus from China boosted equities markets.
U.S. shares seesawed after a stronger open, a more muted reaction after Europe's equities were buoyed by an 8 percent jump in Japanese stocks and the prospect of more stimulus from China.
Oil prices remained in retreat on concerns about swollen inventories, high global production and the increasing likelihood that Iranian barrels will return to export markets even as slowing growth in China threatens demand.
"The failure of oil markets to move higher on the back of this macroeconomic optimism calls fresh attention to the oil market's weak direct physical fundamentals," Tim Evans, energy futures specialist at Citi Futures, said in note.
The U.S. summer driving season is ending. Gasoline demand in the United States has been supportive for oil prices at a time when the global demand picture is clouded by worries about China's economy.
The U.S. government on Wednesday left unchanged its outlook for a decline in 2016 U.S. crude oil production, but lowered its 2015 growth forecast.
In its short term energy outlook, the U.S. Energy Information Administration said that production in 2016 would fall by 400,000 barrels per day (bpd) to 8.82 million bpd. The 2015 crude oil output forecast was lowered to 500,000 bpd of growth, from 650,000 bpd of growth previously.
Traders awaited a fresh snapshot of U.S. oil inventories from industry and government, starting with American Petroleum Institute (API) data due at 4:30 p.m. EDT.
Analysts surveyed by Reuters on Tuesday expected crude stocks to be up slightly.
While Saudi Arabia's crude oil production dipped by 100,000 barrels per day (bpd) in August, the Organization of the Petroleum Exporting Countries continued to produce close to record volumes.
Russia and Mexico have indicated they will not cut production, cooling speculation that some producers might organize to lower output to support prices.
Britain's oil and gas industry association said the country's output is set to post a gain in 2015, the first in 15 years, reflecting investment in more efficient technology.
Oil prices are off more than 50 percent since June 2014 because of the global supply glut. In recent weeks, oil fell to 6-1/2-year lows before rallying in volatile trading after a stock market slide in China sent global equities and commodities prices tumbling.