U.S. stock futures edged lower Tuesday, with the S&P 500 index, the Nasdaq and the Dow all down at least 0.3%.
Companies began reporting earnings before the bell.
DirecTV said that its quarterly revenue expanded and so did net income, driven by the company's stock repurchasing.
At T-Mobile US, quarterly revenue grew, and the wireless company said it added one million subscribers. Company shares rose 4% in premarket trading.
AOL reported double-digit revenue growth for the quarter year-to-year, but a 90% plunge in net income. The company's stock rose 3% in premarket trading.
Tesla Motors and 21st Century Fox are due to report in the afternoon.
On the economic front, the Institute for Supply Management will release its latest monthly reading on the health of the services industry at 10 a.m. ET.
U.S. stocks finished slightly higher Monday. Major U.S. indexes are trading near all-time highs, supported by the U.S. Federal Reserve's historic stimulus program, which is pumping billions of dollars into the financial system each month. This has also given a boost to stock markets around the world.
European markets moved lower by 0.6% in morning trading as investors digested the European Commission's latest economic forecast. A surprise fall in inflation last month has cast fresh shadows over the health of the European economy.
Asian markets ended with mixed results. Japan's Nikkei slipped 0.2% and Hong Kong's Hang Seng dropped 0.7%, while the Shanghai Composite index added 0.4%.