Futures on major U.S. stock indices point to a lower opening Wednesday ahead of new home sales data for April and a European Union summit.

Futures on the S&P 500 are down 0.68 percent, futures on the Dow Jones Industrial Average are down 0.66 percent and Nasdaq 100 futures are down 0.65 percent.

Investors are likely to focus on the new home sales data for April after Tuesday's data showed that sales of previously owned homes rose 3.4 percent during the month, the highest in two years, reversing three months of decline and suggesting that housing market recovery was gaining some traction.

Sales of new houses, which measure the annualized number of new residential buildings that were sold during the previous month, are expected to rise by 2.9 percent to 337,000 in April after plunging 7.1 percent to 328,000 in March.

European stock markets plunged ahead of the informal summit of European leaders in Brussels, where they will discuss measures to handle the weakening economic condition. Germany and France have already promised their support for the continued efforts to keep Greece in the euro zone. It is possible that in the meeting Germany and France might air out their differences in dealing with the economic situation.

Today's informal EU Summit is likely to disappoint. After a show of 'conciliation' at last weekend's G8 Summit, Germany and France are likely to show their differences over the fiscal compact, said a note from DBS Group Research.

Meanwhile, concerns over a messy Greek exit from the euro zone intensified after a report former Greek prime minister Lucas Papademos said the debt-ridden country was considering the possibility that it might have to leave the 17-member currency bloc.

On the corporate front, shares of Dell Inc. (Nasdaq: DELL) will be in focus as its first-quarter profit fell short of expectations. Adjusted net profit was 43 cents per share, down from 55 cents per share last year and below Reuters' estimation of 46 cents per share. Dell shares slumped 13.3 percent to $13.10 in premarket trading.

Guess Inc. (NYSE: GES) on Tuesday reported first-quarter net income of $26.6 million or 30 cents per share on revenue of $579.3 million, above analysts' estimation of 26 cents per share on revenue of $569.85 million.

On the earnings front, Big Lots, NetApp, Hewlett-Packard, Pandora Media, American Eagle Outfitters and Toll Brothers will report their quarterly results.

Asian stock markets ended lower Wednesday as renewed concerns of Greece's probable exit from the euro zone dampened sentiment while the widened Japanese trade deficit in April also weighed.

Japan reported a rise in trade deficit in April compared to a year earlier as the nuclear energy crisis has resulted in an increase in oil and gas imports. Trade deficit in April was 520.3 billion yen ($6.5 billion) compared to a deficit of 477.7 billion yen a year ago.