U.S. stocks dropped more than 1 percent on Monday, with the S&P 500 closing below a key technical support level, as declines in energy and airline shares led a late-day selloff.
The S&P energy sector lost 2.9 percent, extending recent losses. It is down 7.6 percent for the last three sessions, its worst three-day slide since September 2011.
Five of the 10 S&P 500 sector indexes — industrials, telecommunications, consumer discretionary and materials —were in negative territory for the year.