U.S. stock index futures point to higher opening Wednesday, but investors remain watchful amid concerns that the sluggish global economy and the euro zone debt burden will hurt the earnings of companies.

Futures on the Dow Jones Industrial Average were up 0.26 percent, futures on the Standard & Poor's 500 index were up 0.28 percent and futures on the Nasdaq 100 index were up 0.23 percent.

Market participants are expected to closely watch the second quarter earnings releases over the coming days. Investors are concerned that the profit growth of companies has been impaired by the weakening global economy.

Investors are likely to focus the trade balance to be reported by the Bureau of Economic Analysis Wednesday. The trade deficit, which measures the difference in value between imported and exported goods and services over the reported period, is expected to decline to $48.5 billion in May from $50.1 billion in April.

The Federal Open Market Committee (FOMC) will release Wednesday the minutes of its June 19-20 meeting. The minutes offer detailed insights into FOMC's stance on the monetary policy.

Marginal progress at the meeting of the European finance officials in Brussels, with the decision to furnish Spain with the first 30 billion euros ($37 billion) of funds for its banks, could help the market sentiment. At the same time, investors feel that this is only a minor step ease the debt burden in the euro zone.

Hopes of further stimulus from the Federal Reserve may offer some solace to markets, but the market players have the concern that the Fed is unlikely to be close to a further round of quantitative easing.

On Tuesday, the U.S. markets fell as investor sentiment continued to be negative following concerns about the second quarter earnings releases over the coming days to turn out to be disappointing. There is the increasing concern among market players that the economic slowdown in the euro zone will affect the earnings.

The Dow Jones industrial average fell 0.65 percent, the S&P 500 Index was down 0.81 percent and the Nasdaq Composite Index declined 1 percent.

Major European indices fell as investor sentiment remained fragile following concerns about the worsening economic condition in the euro zone. London's FTSE 100 was down 28.31 points, Germany's DAX 30 index fell 25.85 points and France's CAC 40 declined 23.27 points.

Asian markets also fell Wednesday following global cues. Market players were concerned that the euro zone's debt burden would worsen global economic downturn.