NEW YORK (TheStreet) -- Stock futures were moving lower as the Federal Reserve wraps up its March meeting. Fed Chair Janet Yellen will hold a press conference Wednesday afternoon in which she is expected to hint as to when an interest rate hike might occur.

S&P 500 futures were down 0.41%, Dow Jones Industrial Average futures fell 0.5%, and Nasdaq dropped 0.37%. 

The Fed will publish economic forecasts and a statement during the afternoon, which could cause short-term volatility over the session. Investors will watch whether the Fed removes its "patient" phrasing, a move which could signal a rate hike as soon as the summer. 

"We look for the curve to whipsaw as Yellen leans against any overly large market reaction, stressing the 'data dependent' theme and noting that the Fed will begin hiking rates only when there is 'reasonable confidence' that inflation is moving toward their 2% target," said TD Securities' U.S. strategist Gennadiy Goldberg. 

European shares were mixed as a protest outside the European Central Bank in Frankfurt turned violent. Around 10,000 protestors were involved in anti-austerity demonstrations outside of the headquarters. Germany's DAX was down 0.71%, though the FTSE 100 in London added 0.66%. 

China's Shanghai Composite rose for its sixth straight session, adding 2.1% as investors await the next round of government stimulus. Economic data in the world's second-largest economy has shown significant weakness recently. On Wednesday, data showed China's property prices falling 5.7% in February, the sixth month of declines.

Japan's Nikkei closed 0.55% higher to a 15-year high as exports grew at a faster-than-expected pace of 2.4% in February, their sixth straight month of increases and far better than estimates of 0.3%. Sony (SNE) - Get Report helped to push markets higher after reporting better-than-forecast quarterly results. U.S.-listed shares of the Japanese company added nearly 5%. 

Chinese e-commerce site Alibaba (BABA) - Get Report was under pressure on Wednesday as 18% of its shares expire from their 180-day lock-up period following the company's September public offering. Shares were down 0.71% in premarket trading. 

Crude prices were falling again with West Texas Intermediate down 2.7% to $42.31 a barrel. Late Tuesday, the American Petroleum Institute reported a 10.5-million-barrel increase in crude inventories over the week ended March 13, far higher than a forecast increase of 3.7 million barrels. 

Oracle (ORCL) - Get Report shares were up nearly 2% in premarket trading after the tech company reported earnings of 68 cents a share in the three months to February, level with a year earlier, as currency exchange undercut sales and profits. Revenue missed estimates with total sales of $9.32 billion showing no growth from a year earlier.

Adobe (ADBE) - Get Report tumbled 4% after issuing soft guidance for its current quarter. The software company expects earnings as high as 47 cents a share in its second quarter, below average consensus of 48 cents.

FedEx (FDX) - Get Report dropped 1% as annual guidance missed estimates. Though its third quarter was better than expected, full-year earnings expectations of between $8.80 and $8.95 a share missed expectations of $8.97. 

General Mills (GIS) - Get Report climbed nearly 1% after beating third-quarter profit estimates by 3 cents a share and recording a 3% increase in net sales on a constant-currency basis.