Canadian heavy crude has slipped back into a bear market, with the price of Western Canada Select down more than 20 per cent from its April 9 peak.

The oil sands settled down nearly 10 per cent at $41.35 per barrel on Thursday. WCS fell along with other types of crude including the North American benchmark West Texas Intermediate, which traded below US$60 per barrel Thursday for the first time since the end of March amid worries over the U.S. and China’s trade dispute and a surprise jump in crude inventories.

Canadian oil hit record lows last year but prices began to march higher after then-Alberta premier Rachel Notley imposed mandatory production cuts at the beginning of January.

Curtailments have since eased as prices have improved. The production limit was set at 3.68 million barrels a day for this month and 3.71 million barrels for June, up 150,000 barrels from when the production cuts were enacted.

Some energy executives at companies including Canadian Natural Resources Ltd. and Cenovus Energy Inc. have applauded the curtailment program for stabilizing the price of WCS, while others have said they benefited from the steep discount.