U.S. stock-index futures pointed mostly lower Tuesday as Asian and European stocks mirrored Wall Street's losses from the previous session, which were sustained after activist investor Carl Icahn said he was "very cautious" on equities.
Speaking at the Reuters Global Investment Outlook Summit on Monday, Icahn said he could see a 'big drop" in stock values, because earnings at many companies were driven more by low borrowing costs than strong management. Following his words, the Dow fell back below 16,000 points, having risen above it for the first time ever earlier in the session.
All key European bourses and sectors posted losses on Tuesday morning and Asian equity markets were mostly lower as well. Comments from New York Federal Reserve President William Dudley also weighed on sentiment, with Dudley optimistic about the U.S. economic recovery, usually taken as a sign of support for the central bank reducing its stimulus program soon.
(Read more: European shares turn cautious on Fed stimulus)
"The most likely outcome is that Bernanke toes the party line by stating that tapering is dependent on the economic data. But he is unlikely to specify what constitutes the substantial improvement in labour market conditions that the Fed is looking for," said Capital Economics' Paul Dales in a research note.
Data out during Tuesday's session included third quarter employment costs, which rose marginally in the third quarter, pointing to tame wage inflation that should let the Fed maintain its bond-buying program.
Earnings ahead of Tuesday's open had Best Buy warning that its efforts to keep up with discounts being offered by competitors during the holiday season would dent fourth-quarter profitability, with shares of the consumer-electronics retailer falling in pre-market trading. Campbell Soup's first-quarter results fell short of estimates, with the company cutting its outlook for the year. Home Depot, the world's largest home improvement retailer, posted third-quarter sales of $19.5 billion for the third quarter, a 7.4 percent increase on the year before.
Tesla Motors declined after the U.S. national Highway Traffic Safety Administration started an investigation into fires related to its electric cars.
(Read more: Housing recovery propels Home Depot earnings beat)
Correction: This article has been updated to reflect that Best Buy, Campbell Soup and Dick's Sporting Goods report earnings on Tuesday.
—By CNBC's Katy Barnato