Stock index futures pointed to a lower open on Wall Street on Wednesday, with futures for the S&P 500 down 0.2 percent, Dow Jones futures down 0.1 percent and Nasdaq 100 futures down 0.2 percent at 0900 GMT (5 a.m. ET).
The U.S. Federal Reserve's decision on interest rates was due at 1630 GMT when the focus will be on the statement and press briefing that follow.
The central bank's quarterly forecasts will likely be revised down to reflect recent weakness in the recovery, although Fed Chairman Ben Bernanke will most probably reiterate his forecast for a rebound in the second half, while investors look for clues on new measures to support the economy as the Fed's second quantitative easing program comes to an end.
European shares were down 0.5 percent in morning trade, as investors took a cautious stance ahead of the Fed.
U.S. company Dentsply International
PostRock Energy Corp
On the earnings front, investors awaited results from FedEx Corp
According to Societe Generale's cross asset research team, net short positions by hedge funds on the S&P 500 have recently increased, while hedge funds have also been turning increasingly short government bonds, especially at the long end of the curve, although overall positions remain fairly limited.
Despite the absence of a clear solution to the euro zone sovereign crisis, net sellers of the dollar are gradually returning against the euro, SocGen's team also said in a note.
U.S. stocks posted gains for a fourth day on Tuesday on growing hopes Greece will avoid a debt default, adding momentum to the market's recent rebound.
The Dow Jones industrial average <.DJI> rose 109.63 points, or 0.9 percent, to 12,190.01 at the close. The Standard & Poor's 500 Index <.SPX> gained 17.16 points, or 1.3 percent, to 1,295.52. The Nasdaq Composite Index <.IXIC> climbed 57.60 points, or 2.2 percent, to 2,687.26.
(Reporting by Blaise Robinson; Editing by Dan Lalor)