Futures Lower Amid EU Jitters; GE Slides

U.S. stock index futures were lower Friday following a three-day rally as worries over Europe resurfaced and as investors sifted through another batch of earnings.

“You have to wonder why we were up in the first place,” said Joe Saluzzi, co-manager of trading at Themis Trading. “European problems haven’t gone away, volume’s been light, earnings haven’t been that great—I think the rally was overblown.”

Euro zone finance ministers agreed to lend up to 100 billion euros to Spain so it can recapitalize its banks, but the exact size of the loan will probably only be determined in September.

Europe's top shares fell, but remained on course for a seventh straight week of gains as expectations of further stimulus measures in the U.S. and robust corporate earnings offset a weak macroeconomic outlook.

General Electric reported earnings that edged past expectations, but revenue was lighter than estimates. The company added it was finding ways to grow despite a hazy economic outlook. Shares slipped in pre-market trading. GE is the minority owner of NBCUniversal.

Google announced core Internet business increased revenue by 21 percent in the second quarter, easing Wall Street worries that a slumping global economy would take a toll on the company's online advertising.

Fellow tech giant Microsoft reported earnings excluding one-time items that beat analysts' expectations though the software giant posted its first net loss since it went public in 1986 and delivered revenue that fell short of expectations.

Schlumberger edged higher after the oilfield services company, posted a 5 percent increase in profit.

Meanwhile, Xerox declined after the copy machine maker slashed its full-year earnings target after it reported lower quarterly results amid tough economic conditions in Europe.

No major economic reports are expected today.

On the tech front Dell’s new software chief plans to increase the size of the business five-fold, a target that could eventually account for at least 25 percent of the PC maker's profits.

And Yahoo’s new CEO Marissa Mayer's compensation package could total more than $70 million in salary, bonuses, restricted stock and stock options over five years, according to a regulatory filing.

—By CNBC’s JeeYeon Park (Follow JeeYeon on Twitter: @JeeYeonParkCNBC)

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