Investing.com -- U.S. stocks were mixed on a volatile, choppy day of trading as European Central Bank president Mario Draghi spooked global markets by vowing not to reduce rates any further after its Governing Council approved a wide range of stimulus measures on Thursday.
Earlier, the ECB unveiled a comprehensive set of easing initiatives on Thursday aimed at boosting economic growth throughout the euro zone and staving off deflation. The Governing Council used nearly all of the tools at its disposal to stimulate the economy by lowering three key rates at the meeting and extending the scope of its comprehensive Quantitative Easing program. Draghi's comments, however, triggered a sharp reversal on global equity and foreign exchange markets, as investors worried that Thursday's decisive moves could be the ECB's last attempts to rescue a flagging euro zone economy.
The Dow Jones Industrial Average fell by 5.23 or 0.03% to 16,995.13, while the S&P 500 Composite index gained 0.31 or 0.02% to 1,989.57. Previously, both the Dow and the S&P 500 closed higher in six of seven trading sessions dating back to last week. The Dow swung by as much as 300 points on Thursday. The NASDAQ Composite index, meanwhile, dipped by 12.22 or 0.26% to 1,989.57, as pharmaceutical and media stocks lagged.
On the S&P 500, six of 10 sectors closed in the red, as stocks in the Technology and Industrials sectors lagged. Stocks in the Basic Materials and Telecommunications industries led, each gaining more than 0.3% on the session.
The top performer on the Dow was Merck & Company Inc (NYSE:MRK), which gained 0.56 or 1.07 to 52.92 after the pharmaceutical giant announced plans to discontinue to a 20-year joint venture to sell vaccines with Sanofi (PA:SASY) in the euro zone. The worst performer was EI du Pont de Nemours and Company (NYSE:DD), which fell 1.29 or 2.03% to 62.16. Shares in DuPont (NYSE:DD) are down approximately 16% since the multinational conglomerate announced a $130 billion merger with Dow Chemical Company (NYSE:DOW) in mid-December.
The biggest gainer on the NASDAQ was Dollar Tree Inc (NASDAQ:DLTR), which added 3.01 or 3.92% to 79.74 after chief rival DG saw its sales surge by 7% over the last quarter. The worst performer was Vertex Pharmaceuticals Inc (NASDAQ:VRTX), which fell 2.34 or 2.76% to 82.29. Vertex Pharmaceuticals (NASDAQ:VRTX) has come under heavy pressure in recent weeks amid allegations of price gouging with its Cystic Fibrosis drug.
Dollar General was the top performer on the S&P 500 after surging 7.82 or 10.40% to 83.03. During the quarter, the company's revenues soared as customer demand rose for candy, tobacco products and perishables. The worst performer was Whole Foods Market Inc (NASDAQ:WFM), which fell 1.00 or 2.95% to 32.92.
On the New York Stock Exchange, declining issues outnumbered advancing ones by a 1,844 to 1,241 margin.