Apple accounts for a significant proportion of the overall earnings of Standard & Poor's 500 .SPX components. S&P 500 earnings are expected to show a rise of 5.7 percent in the second quarter from a year ago. Excluding the maker of the iPad, the rise is 4.8 percent, according to Thomson Reuters data.

Apple's results, due Tuesday, could help stocks build on this week's gains and counter investor worries over the euro zone crisis. More signs of financial stress in Spain on Friday caused stocks to give back some of the week's increase. The S&P 500 ended 0.4 percent higher for the week.

"Apple can drive the whole (tech) group," said Daniel Morgan, who helps manage about $3.5 billion at Synovus Trust Company in Atlanta.

"There's a huge psychological component as it relates directly to Apple. If they just blast numbers like they did last quarter, then obviously the perception will be everybody else did pretty good and Apple did fabulous."

Apple's expected strong performance is mainly why technology earnings growth has held up better than other S&P 500 sectors. The expected growth rate for the sector has gone from 6.9 percent in April to 8.7 percent as of Friday, the data showed.

Apple's earnings for the quarter are seen at $10.38 a share, based on Thomson Reuters I/B/E/S, which includes estimates from 43 analysts. That compares with a profit of $7.79 a share for the year-ago quarter.

Morgan said Apple's growth has largely depended on the success of its new products. "For the stock, to continue its trajectory at the pace it has, it's critical that they release these new products," he said. Apple's shares are up 49.2 percent for the year so far.

Apple does not give any clues on its future products, but the California company is widely expected to release its next-generation iPhone later this year. Wall Street has also set its heart on Apple launching a new "mini iPad" and the long-awaited television set in the near future.

Investors are likely to be just as keen to hear from Facebook when it reports on Thursday. Facebook's first results following its market debut could give investors another chance to indicate how they feel about the stock since its disappointing initial public offering.

Shares of Facebook, one of the most closely watched IPOs ever, lost ground after technical problems with its market debut on Nasdaq and as investors questioned its ability to rapidly increase advertising revenue.

Analysts said an earnings miss by Facebook could be disastrous for the stock, which closed Friday at $28.76, below its $38 offering price.

Investors are looking for executives to address a litany of concerns about the business, such as the efficacy of its online ads and the company's nascent efforts in mobile advertising.

Tech results also will be closely watched for signs of weak demand overseas, particularly from Europe. Other technology companies expected to report next week include Texas Instruments (TXN.O) and Amazon.com (AMZN.O). Of the S&P sectors, technology has the highest sales exposure to Europe at about 25 percent, according to a Bank of America/Merrill Lynch research note.

Among the other 138 S&P 500 companies reporting earnings are Ford Motor Co (F.N), United Parcel Service (UPS.N) and Whirlpool Corp (WHR.N).

While the majority of companies have beaten earnings expectations, revenue performance has been the worst for S&P 500 companies since the first quarter of 2009.

With results in from 116 companies, just 43 percent of companies are beating revenue expectations.

Sixty-seven percent of companies are beating earnings estimates, compared with a long-term average of 62 percent, Thomson Reuters data showed.

"With global growth slowing down, it's not surprising we're going to see some mixed numbers on the revenue side," said Natalie Trunow, chief investment officer of equities at Calvert Investment Management in Bethesda, Maryland, whose firm manages about $13 billion in assets.

While earnings are expected to dominate stock investors' attention in the coming week, the euro zone crisis is still capable of taking the spotlight.

"It's the default thing for people to focus on," said Eric Kuby, chief investment officer at North Star Investment Management Corp. in Chicago.

Spain will tap the markets Tuesday when it sells three- and six-month bills. It will also sell three- and five-year bonds on August 2. Spain's 10-year bond yields hit a euro-era high of 7.3 percent on Friday.

The week's U.S. economic data includes the Markit U.S. Manufacturing Purchasing Managers Index for July, due on Tuesday. June's reading marked the lowest showing since December 2010.

(Reporting By Caroline Valetkevitch; Editing by Kenneth Barry)

• A Permanent Economic Emergency