U.S. stock futures dipped, on Wednesday, preceding what could be a lower opening in the stock markets, as investors await GDP data, an employment report, the Chicago PMI and the outcome of the two-day meeting of the Federal Open Market Committee, or FOMC.

Futures on the Dow Jones Industrial Average were down 0.04 percent, while futures on the Standard & Poor's 500 Index were down 0.06 percent and those on the Nasdaq 100 Index were down 0.11 percent.

Above all, investors are expected to be guided by the outcome of the FOMC's two-day policy meeting, which concludes on Wednesday.

Investors will closely watch for further hints on how long the Fed intends to continue its massive asset-purchase program when the committee is expected to release a statement at 2 p.m. EDT on Wednesday. Analysts expect the Fed to maintain its current positions on interest rates and monetary policy.

“It will probably wait until September to begin tapering its monthly asset purchases. At most, the accompanying policy statement might include some modest changes, such as highlighting the further improvement made in the labor market,” David Madani, an analyst at Capital Economics, wrote in a research report.

Meanwhile, GDP data for the second quarter is due to be released at 8.30 a.m. EDT on Wednesday and analysts polled by Bloomberg expect that the U.S. economy is likely to have slowed to a 1 percent growth in the second quarter from an annualized 1.8 percent growth registered in the first three months of the year.

The GDP data will be closely watched by both the Federal Reserve and financial markets as the Fed has indicated that the future of the bond-buying program will depend on the strength of economic indicators.

“This release will also include revisions to the historical data, which for the first time will incorporate investment in research and development. That will boost the level of GDP by around 3 percent, although historical growth rates may be largely unchanged,” Madani wrote.

Investors are also likely to focus on the ADP National Employment Report, which is a measure of the monthly change in non-farm private employment, based on the payroll data of approximately 400,000 U.S. business clients, due to be released at 8.15 a.m. EDT. The index, which comes two days ahead of the official non-farm payroll report, is expected to decline to 180,000 for July from 188,000 recorded in the previous month.

The Chicago Purchasing Managers' Index, or PMI, which determines the economic health of the manufacturing sector in the Chicago region, is expected to show a reading of 54 points in July, up from 51.6 points recorded in the previous month.

On the earnings front, American Tower Corp (NYSE:AM), Comcast Corporation (Nasdaq:CMCSA), Exelon Corporation (NYSE:EXC), Phillips 66 (NYSE:PSX), The Southern Company (NYSE:S) and PG&E Corporation (NYSE:PCG) will report their quarterly earnings before the market hours. CBS Corporation (NYSE:CBS), MetLife Inc (NYSE:MET) and Williams Companies, Inc. (NYSE:WMB) will report quarterly earnings after market hours on Wednesday.

European markets opened lower on Wednesday, as disappointing retail sales data from Germany and a drop in French consumer spending dented investor confidence. There is more data to emerge out of Europe on Wednesday including Germany’s unemployment data and consumer price inflation and unemployment rate for the euro zone. European investors are also expected to be watching the FOMC monetary policy decision and GDP data from the U.S.

The Stoxx Europe 600 index fell 0.35 percent, London’s FTSE 100 was down 0.12 percent, Germany's DAX-30 was down 0.50 percent and France's CAC-40 was trading down 0.34 percent.

Germany’s retail sales, unexpectedly declined 1.5 percent in June – the biggest fall this year – after rising 0.7 percent in the previous month, according to data released on Wednesday. Meanwhile, French consumer spending declined 0.8 percent in June after gaining 0.7 percent in the previous month. Analysts had expected consumer spending to increase by 0.1 percent in June.

In Asia, markets traded mixed on Wednesday with China’s shares trading up on stimulus hopes, after the politburo of the Chinese Communist party said it would take measures to maintain steady growth. The Shanghai Composite index ended up 0.19 percent while Hong Kong’s Hang Seng Index lost 0.41 percent.

Australia’s S&P/ASX 200 ended up 0.1 percent after gaining up to 1 percent in intra-day trade on interest-rate cut hopes. Japan’s Nikkei fell 1.45 percent, South Korea’s KOSPI Composite index closed down 0.16 percent and India’s BSE Sensex was trading down 0.72 percent in late-afternoon trade.