U.S. stock index futures dipped in low volume on Wednesday following three days of gains on Wall Street as traders awaited more signals about central bank action in the euro zone.
Growing expectations the European Central Bank could act soon to contain the euro zone's debt crisis and a Federal Reserve seen ready to take measures to stimulate the economy have triggered a recent rally in equities, with the S&P 500 up for a fifth week running and at levels not seen since early May.
The Canadian dollar opened at 100.30 cents US, up 0.05 of a cent from Tuesday's close.
Spanish benchmark 10-year yields briefly rose above 7 per cent, underscoring the cautious tone from investors recently disappointed by lack of coordination from European officials in their efforts to reignite the economy.
The Bank of England sharply cut its forecast for medium-term growth in Britain's economy but it gave little indication that it would rush to pour further stimulus into the economy.
S&P 500 futures fell 3.1 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration of the contract. Dow Jones industrial average futures lost 14 points and Nasdaq 100 futures fell 1 point.
Investors awaited preliminary second-quarter U.S. productivity and unit labor costs due at 8:30 a.m. ET. Economists in a Reuters survey expect productivity to rise 1.3 per cent versus a 0.9 per cent decline in the revised Q1 report. Unit Labor costs are expected to rise 0.6 per cent compared with a 1.3 per cent rise in previous report.