LONDON -- Stock index futures at 7 a.m. EDT indicated that the Dow Jones Industrial Average (^DJI 0.76%) may open down by 0.28% this morning, while the S&P 500 (^GSPC 1.29%) may open 0.33% lower.

European markets edged lower this morning as investors reacted to several downbeat earnings reports and turned cautious ahead of today's U.S. GDP data, due at 8.30 a.m. EDT. Consensus forecasts suggested that U.S. GDP may have risen by 3% during the first quarter of the year on an annualized basis, after rising by 0.4% in the final quarter of 2012. Today's other main economic report was April's University of Michigan consumer sentiment survey, which was due at 9.55 a.m. and was expected to show a slight rise in consumer sentiment to 74.0, up from 72.3 in March.

Companies due to report earnings before the opening bell this morning included Chevron, Burger King and Goodyear Tire. Forest products company Weyerhaeuser reported a 351% increase in first-quarter net earnings to $144 million or $0.26 per share, up from $41 million and $0.08 per share for the same period last year. Tyco International said that it would take a $124 million charge on its first-quarter earnings, much of it related to an environmental issue at a Wisconsin plant. The charge caused quarterly earnings to fall to $0.16 per share, down from $0.29 per share for the same period last year.

Several major Nasdaq stocks could be actively traded when markets open this morning. Amazon fell 3.2% in German trading this morning, after the retailer said that earnings for the second quarter would fall within a range from an operating loss of $340 million to a profit of $10 million, substantially below analysts' average forecast for a profit of $165 million. Expedia slid 5.3% in after-hours trading last night, after the online travel firm's CFO said that increased competition for its Hotwire travel website meant that earnings would be $20 million to $30 million lower than expected in 2013. Completing our trio of falling Nasdaq stocks, Starbucks' share price fell by 3% in German trading this morning, after it missed revenue expectations in its latest quarterly results. CEOTroy Alstead told Bloomberg that "Europe continues to be just a challenging place for us."