Worries about Europe's debt crisis flared up again on Friday, after Italy had to pay 7.8 percent to borrow for two years at a debt auction.
Less than two hours before the opening bell, Dow Jones industrial average futures are down 64 points, or 0.57 percent, to 11,170. The Dow has already lost 4.6 percent this week, putting the average on track for its worst week since September.
S&P 500 index futures are down 6, or 0.6 percent, to 1,153. Nasdaq 100 futures are down 12, or 0.6 percent, to 2,149.
Trading will end at 1 p.m. Eastern time. U.S. markets were closed on Thursday for the Thanksgiving holiday.