Investors are examining new data on the housing market Tuesday morning.
The S&P Case/Shiller Home Price Index for February showed prices dropped in February from January in 16 of the 20 cities it tracks.
Later, investors will see new home sales for March, due at 10:00 a.m. ET. New data on April consumer confidence are also expected.
Also a focus for investors: Facebook, which Monday reported its first quarter-to-quarter revenue slide in at least two years, a sign that the social network's sizzling growth may be cooling as it prepares to go public in the biggest ever Internet IPO.
Boeing Co has pulled ahead of Airbus in a race to win an aircraft order potentially worth more than $15 billion at list value with United Continental Holdings, but intense negotiations lie ahead to close a deal that Airbus is unlikely to abandon without a fight, industry sources said.
Investors awaited a flurry of corporate earnings on Tuesday from companies including Apple Inc, The McGraw-Hill Cos, 3M, AT&T Inc and United Technologies.
U.S. stocks fell on Monday as political turmoil in Europe cast doubts on the euro zone's ability to push through measures to end its debt crisis and as Wal-Mart shares sank on concerns about a bribery investigation in Mexico.