U.S. stock index futures were lower on Wednesday ahead of the release of the July minutes from the Federal Reserve's last policy meeting.
The minutes are due at 2 p.m. ET and could provide fresh insight into when the central bank plans to taper off its $85 billion per month asset purchases.
European shares traded flat and Asian markets pared early gains on Wednesday on concerns about the potential impact of a reduction in the Fed's monetary stimulus program.
Fed watchers disagree on how much detail will be provided but Michael Hewson, senior market analyst at CMC Markets, told CNBC the latest minutes had the potential to be a "big let-down".
"The only thing that might prompt some price movement is if policymakers deviate in any way from the previous minutes and give more clarity about the timing and constitution of a possible tapering program," he said.
U.S. bonds treaded water on Wednesday, ahead of the minutes, with yields on benchmark 10-year Treasurys at 2.85 percent, down from a two-year peak of 2.90 on Monday.
"Tapering this year is likely to remain as a consensus, although with no explicit timing. Still, at the margin, the greater risk tonight appears to be a conclusion that tapering might come a little later than September," said Bank of Tokyo-Mitsubishi's Derek Halpenny, in a morning research note.
On the economic front, the National Association of Realtors is scheduled to release data on July home resales at 10 am ET. Economists in a Reuters survey forecast a total of 5.15 million annualized units versus 5.08 million annualized units in June.
Weekly mortgage applications declined for a second week and rising interest rates put a damper on refinancing activity, according to data from the Mortgage Bankers Association.
Among earnings, Target declined after the retail giant warned its annual earnings will likely be near the lower end of its previous forecast as the company anticipates ongoing cautious consumer spending.
Staples plunged after the office supplies retailer posted earnings and revenue that missed projections, citing weakness in its retail stores and international operations.
Meanwhile, Lowe's rallied after the home-improvement company posted topped quarterly expectations and boosted its full-year outlook. The news came a day after rival Home Depot posted strong earnings results.
Goldman Sachs experienced a glitch on Tuesday that resulted in a large number of erroneous single stock and ETF options trades. Many of the trades may wind up being erased, but the error could still cost the firm over $100 million, according to a person familiar with the situation.