Traders Richard Scardino, left, and Gregory Rowe, center, confer on the floor of the New York Stock Exchange Monday, Jan. 5, 2015. US stocks opened lower Monday, led by declines in energy stocks as the price of oil plunged again.  (AP Photo/Richard Drew)

Traders Richard Scardino, left, and Gregory Rowe, center, confer on the floor of the New York Stock Exchange Monday, Jan. 5, 2015. US stocks opened lower Monday, led by declines in energy stocks as the price of oil plunged again. (AP Photo/Richard ... Drew) (The Associated Press)

Price of crude oil slumps, dragging down energy companies and the rest of the stock market

Energy Associated Press

Another plunge in the price of oil is driving stocks sharply lower in afternoon trading.

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Energy stocks slumped as the price of crude briefly dipped below $50 a barrel.

The Dow was down 295 points, or 1.7 percent, to 17,539 as of 12:43 a.m. Eastern time. It was down as much as 315 earlier.

The Standard & Poor's 500 index fell 33 points, or 1.6 percent, to 2,024. The Nasdaq composite fell 56 points, or 1.2 percent, to 4,671.

Energy companies had the worst declines in the S&P 500 index. Denbury Resources and Noble Energy each lost 9 percent.

The euro sank to a nine-year low as traders worried about whether Greece will stay in Europe's currency union.