Stocks fell by mid-afternoon Monday as a slide in crude oil prices picked up speed.
The S&P 500 was down 0.68%, the Dow Jones Industrial Average fell 0.41%, and the Nasdaq slid 0.6%.
Crude oil prices continued to spiral lower on Monday after a 9% jump to end last week. West Texas Intermediate crude oil fell 4.7% to $30.67 a barrel after spending the morning trading above $31.
The turn lower on Monday was tied to comments from Saudi Arabia's state oil giant, Saudi Aramco, suggesting the company is continuing to invest in oil and gas projects despite global oversupply. Saudi Arabia has some of the lowest-costing oil in the world and production could be economically viable at as low as $15 a barrel.
Stocks closed out Friday with their first weekly gain in a month as a surge in crude oil prices triggered a rally in the energy sector and bets of more stimulus out of the eurozone boosted global markets. Crude enjoyed its best one-day gain since August.
McDonald's (MCD) shares traded near record highs after a better-than-expected end to 2015. The fast food chain reported fourth-quarter same-store sales up 5%, above estimates of 3.2%, while profit jumped 16% to $1.31 a share.
SunEdison (SUNE) climbed on reports David Einhorn's Greenlight Capital will appoint a director to the solar company's board. The company has suffered a slumping stock price and a number of C-suite departures recently. An announcement could be made this week.