New York - US stocks finished firmly lower on Wednesday following a volatile session as merger talks between Dow Chemical and Dow member DuPont limited the Dow's decline.
The swings in share prices roughly tracked those in oil, which rallied at mid-session before closing at fresh seven-year lows. Falling commodity prices, along with a surprise rally in the euro, have rattled investors.
"The currency markets and the oil markets have been driving the positioning in equity markets and that's been mostly selling," said Michael James, managing director of equity trading at Wedbush Securities.
The Dow Jones Industrial Average dropped 75.70 points to 17 492.30. The intraday swing of the blue-chip index was more than 350 points.
The broad-based S&P 500 shed 15.97 points to 2 047.62, while the tech-rich Nasdaq Composite Index tumbled 75.38 points to 5 022.87.
DuPont and Dow Chemical both jumped 11.9% on prospects of their combining into the world's biggest chemical company, with annual sales totalling more than $90bn.
Yahoo dropped 1.3% after announcing a retreat from plans to hive off its Alibaba stake and instead seek a "reverse spinoff" of its core internet properties.
Technology stocks were generally weak. Apple fell 2.2% and Amazon, Facebook, Microsoft and Google parent Alphabet all lost between 1.4% and 1.9%.
Big-box retailer Costco Wholesale tumbled 5.4% after net income for the quarter ending November 22 fell 3.2% to $480m due to a 1% fall in comparable sales.
Yoga-gear retailer Lululemon Athletica dropped 13.1% after forecasting fourth-quarter net income of 75-78 cents per share, below the 86 cents projected by analysts.
Gaming giant Wynn Resorts surged 13.2% on news that chief executive Stephen Wynn bought one million shares on the open market, lifting his stake to about 11%.
Auto service chain Pep Boys rose 0.2% after endorsing a takeover offer by Carl Icahn of $15.50 a share as preferable to a pending deal agreed with Bridgestone for $15 a share.