Futures on the S&P 500 fell by about 0.25 percent following similar losses in Europe. The declines were steeper in Asia, with Japan and China losing 1 percent to 2 percent amid weak manufacturing reports and ongoing concerns about a diplomatic row between the two countries.
Economic data was mixed in Europe, with the Eurozone purchasing managers index showing worse-than-expected contraction for September. The German PMI, however, rose to 47.3, surpassing economists' 45.2 consensus forecast.
Attention now focuses on U.S. data. Weekly jobless claims will be announced at 8:30 a.m. ET, followed at 10 a.m. ET by leading economic indicators and the Philadelphia Fed's survey of business conditions.
The commodity and foreign-exchange markets are mirroring the shift toward caution. The U.S. dollar is climbing against most currencies associated with risk-taking, including the euro, Canadian dollar, and Australian dollar. The Japanese yen is higher across the board, which tends to correlate with risk aversion.
Energy, metals, and agricultural foodstuffs are showing similarly cautious trends. Crude oil and gold dropped by about 0.5 percent, while copper is down by almost 2 percent. Wheat, corn, and soybeans are lower as well.
In company-specific news, Adobe Systems is up about 1 percent in early trading. It initially fell on a weak revenue forecast yesterday afternoon, but then rebounded after saying that customers were transitioning to a new revenue model.
Apogee Enterprises, a maker of glass for buildings, and office furniture company Steelcase rallied on strong results.

