NEW YORK (MarketWatch) — The crude-oil collapse continued unabated Tuesday, with the U.S. benchmark closing below $48 a barrel for the first time since April 2009 as worries over Greek debt were added to a litany of bearish factors, including a global supply glut and a rising U.S. dollar.

On the New York Mercantile Exchange, light, sweet crude for delivery in February CLG25, fell $2.11, or 4.2%, to close at $47.93 a barrel, its lowest finish since April 2009.

Brent crude for February delivery on London’s ICE Futures Exchange UK:LCOG5 fell $2.01, or 3.8%, to $51.10, also its lowest level since April 2009.

“There is no compelling reason why oil prices cannot fall further in the near term, but the current market panic looks increasingly overdone,” said Julian Jessop, head of commodities research at Capital Economics, in a note.

Both the oil benchmarks have fallen for six of the past seven trading sessions and lost more than 5% on Monday. Nymex crude saw a 46% decline in 2014 and has dropped an additional 10% in the first three trading days of 2015, according to FactSet data.

“In addition to what is already a very bearish supply-demand profile for oil anyway, over the last few days there’s been an increase in new bearish factors to contend with,” said Mark Keenan, Société Générale’s head of commodities research in Asia.

He said ongoing strength in the U.S. dollar DXY, +0.03% , concerns about Greek debt and the oil-supply glut will mean oil prices will be under significant pressure for the first half of 2015.

Keenan said employment profiles in American shale basins will be early indicators of a decline in oil production, and changes in drilling rig counts, company spending and railcar traffic will also be worth noting.

The U.S. shale revolution, aided by commercialized drilling technologies like fracking and horizontal drilling, has driven the boom in American oil production. This has contributed to the current oil oversupply.

“The oil collapse and concerns of excess global oil and North American natural gas supply should cause an exploration-and-production business-model reassessment in 2015,” Goldman Sachs said in a report last week.

Goldman Sachs expects more announcements about capital expenditure cuts, a reduction in drilling activity in the first half of the year and a downward supply adjustment to oil prices in the second half.

Nymex reformulated gasoline blendstock for February US:RBG5 — the benchmark gasoline contract — fell 3 cents to $1.35 a gallon.