fiscal cliff was standing in the way of stronger economic growth, and that there was no prospect for an agreement if tax rates didn't rise on the wealthiest taxpayers.
The stock of Freeport-McMoRan Copper & Gold Inc fell 16 percent to $32.17 and ranked as the S&P 500's biggest percentage decliner. The company said it was acquiring Plains Exploration & Production Co and McMoRan Exploration Co in two separate deals for $9 billion in cash and stock in a major expansion into energy.
McMoRan Exploration soared 87 percent to $15.82 and Plains surged 23.4 percent to $44.50.
About half of the stocks traded on the New York Stock Exchange closed in positive territory, while about 54 percent of Nasdaq-listed shares ended lower.
Volume was higher than it has been in recent sessions, with about 6.93 billion shares changing hands on the New York Stock Exchange, the Nasdaq and NYSE MKT, above the daily average so far this year of about 6.48 billion shares.