Europe's oil benchmark Monday closed below $50 a barrel for the first time in six years after a leading investment bank predicted the commodity would sink even lower in coming months.
Brent crude for February delivery lost $2.68 to finish at $47.43 a barrel in London, its first close below $50 since April 2009.
US benchmark West Texas Intermediate for February also hit a new multi-year low, shedding $2.29 to $46.07 a barrel on the New York Mercantile Exchange, the lowest close since March 2009.
"At this point, it's really just panic selling out of fear of how low oil prices could go," said market analyst Jasper Lawler at CMC Markets UK.
The drop came as Goldman Sachs sharply cut its forecast for 2015 oil prices, projecting the US commodity would hit $41 a barrel in three months and $39 a barrel in six months, down from the $70 and $75 previously.
Goldman also cut its forecast for Brent oil.
The investment banking firm predicted the oil market would continue to experience oversupply for several months.
As a result, oil prices "need to stay lower for longer," it said.
"The short-cycle nature of capital investments in shale requires that such pressure remain in place long enough to keep capital sidelined while the market rebalances."
Monday's fall came on the heels of a six-month crash in the market that has slashed crude prices by more than 50 percent amid concerns of oversupply and weak global growth.
Other factors cited by analysts for the price drop included the downgrade to Russia's credit rating last week and continued inaction from OPEC.