U.S. stock index futures were slightly lower Monday in a shortened day of trading, amid ongoing worries lawmakers in Washington will be unable to reach a deal to avert the "fiscal cliff."
Trading volume is expected to be light, with the stock market scheduled to close at 1pm ET Monday. Markets will remain closed on Tuesday for Christmas day.
Ongoing worries over the "fiscal cliff"—$600 billion in tax hikes and automatic spending cuts that kick in on January 1—kept investors on edge. With the House of Representatives and the Senate on their Christmas break and President Obama celebrating the Christmas holiday in Hawaii, talks will likely only resume after December 25.
"With no Plan B and the gulf between the parties as wide as ever, there is little to cheer this holiday season. The optimism that had seen the market rally strongly over the last few weeks is diminishing rapidly amid signs that a deal is as far away as ever," said Rebecca O'Keeffe, head of investment at Interactive Investor.
Still, the S&P 500 is on track for its best yearly performance since 2009 with a gain of 13.7 percent year-to-date.
Microsoft slipped after the New York Times reported that sales of the tech giant's new Windows 8 operating system had disappointed PC makers as well as analysts.
Facebook gained after Needham raised its price target on the social-networking giant to $33 from $25.
Research In Motion declined after Exane BNP Paribas cut its target price on the BlackBerry maker to $5.50 from $8.30.
European shares were range-bound with light volumes in a truncated day of trading. Major markets such as Germany, Switzerland and Italy were closed.
—By CNBC's JeeYeon Park (Follow JeeYeon on Twitter: @JeeYeonParkCNBC)
Coming Up This Week:
MONDAY: Market closes at 1pm ET
TUESDAY: Markets closed for Christmas
WEDNESDAY: Weekly mortgage applications, Case-Shiller homeprice index, Richmond Fed mfg index
THURSDAY: Jobless claims, new home sales, consumer confidence, oil inventories, Kansas City Fed survey, Fed balance sheet, money supply
FRIDAY: Chicago PMI, pending home sales, natural gas inventories
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