The stock closed down 1.78% at $8.84.
Brent crude declined to $67.53 a barrel on Monday, its lowest price since October 2009, according to BBC News. U.S. crude dropped 50 cents to $65.65 a barrel and hit an intraday low of $63.72, the lowest price since July 2009.
Brent crude rallied 3.89% to $72.88 in late afternoon trading.
OPEC decided last week not to cut oil production and to keep its target at 30 million barrels per day, a move that could leave the market oversupplied. The announcement sent oil prices spiraling downward, a trend that continued into Monday.
More than 8.8 million shares changed hands Monday, compared to the daily average volume of 4,757,760.