Lingering concerns about oversupply and the health of the Chinese economy pulled oil prices lower in Thursday trading, with key indices approaching 2015 lows.

Brent crude oil prices ticked moderately lower in Thursday trading to $49.41, pulling back from early Wednesday gains sparked by industry data suggesting an increase in demand. West Texas Intermediate, the U.S. benchmark, lost nearly a full percentage point to $44.74, a multi-month low.

WTI hit $44.08 in late January.

Early this week, private payroll processor ADP said the U.S. labor sector, one of the bright spots in the economy, had moderated in recent weeks. The Labor Department said Thursday the advance figure for seasonally adjusted new claims for unemployment insurance for the week ending Aug. 1 was up by 3,000.

The low price of crude oil is crimping investments in exploration and production and prompting many companies to cut back on staff. Labor Department data show new claims for unemployment in Texas increased 2.5 percent for the week ending Aug. 1.

Late July dives in crude oil prices were triggered in part by dual crashes in the Chinese stock market. Government intervention in response to suspicious market activity arrested some of the declines, though CITIC Securities, the largest trader of its kind in China, saw net profit drop by more than 20 percent from June.

Despite the market downturn, some energy companies working in U.S. shale basins are posting an increase in production. Marathon Oil said in its latest quarterly report output from the Bakken shale in North Dakota, the No. 2 oil-producing state, was on the rise despite lower rig deployments.

North Dakota unemployment claims, however, increased from 420 to 683 for the week ending Aug. 1.

Federal data published Wednesday show total U.S. crude oil production increased by 52,000 barrels to 9.5 million barrels per day.