The price of oil in the U.S. slipped below $40 a barrel Friday for the first time since 2009 amid a growing consensus that cheap crude is here to stay.

Oil investors and forecasters, who predicted early in the year that prices would recover in the second half of 2015, now say a rebound is unlikely before the second half of next year or 2017. U.S. government forecasters last week cut their oil-price estimates and see oil holding below $60 a barrel, on average, through 2016.

The shift in sentiment is partly due to the resilience of U.S. oil producers, who are continuing to pump crude at near-record levels despite months of spending cuts, thanks to new efficiencies in drilling technology. An unexpected price rally in the second quarter allowed some companies to lock in profitable prices for next year and add new drilling rigs.

In intraday trading, the benchmark U.S. oil price tumbled as low as $39.86 a barrel on the New York Mercantile Exchange. The futures price later pared losses to finish at $40.45 a barrel, down 2.1%, or 87 cents, on the day.

Brent crude, the global benchmark, fell $1.16, or 2.5%, to $45.46 a barrel on ICE Futures Europe.