* Apple shares up nearly 5 pct, boost Nasdaq
* Dow components Caterpillar, AT&T weigh on blue chip index
* Stocks mixed: Dow down 0.1 pct, S&P flat, Nasdaq up 0.4 pct
By Angela Moon
NEW YORK, July 24 (Reuters) - U.S. stocks were flat on Wednesday as results from blue-chips Caterpillar and AT&T offset gains for the tech sector generated by Apple's stronger-than-expected results.
Shares of Apple, the world's largest technology company, rose 4.3 percent to $436.93 after the iPhone and iPad maker late Tuesday reported earnings and revenues that beat Wall Street's estimates, boosted by a jump in iPhone sales to 31.2 million.
Apple is the most heavy weighted stock on the Nasdaq. Also advance was video game publisher Electronic Arts Inc, whose shares jumped 8.5 percent to $25.86 after the company late Tuesday reported better-than-expected revenue and profit for its first fiscal quarter.
But the gains were offset by Caterpillar and AT&T, which were weighing heavily on the Dow index following their results.
"The earnings season so far has been pretty good for most companies. Investors anticipated good numbers and they got them, although the forecasts haven't been necessarily strong enough to push the market higher," said Rick Meckler, president of LibertyView Capital Management in Jersey City, New Jersey.
"I think the market now stands at a point where you are going to need good economic numbers to really move higher."
As of Tuesday's close, of the 130 companies in the S&P 500 that have reported earnings so far this season, 63.8 percent have beaten analysts' expectations for earnings, but 51.5 percent have fallen short of revenue forecasts. Over the past four quarters, 67 percent of companies have beaten earnings estimates.
The Dow Jones industrial average was down 17.38 points, or 0.11 percent, at 15,550.36. The Standard & Poor's 500 Index was up 0.09 points, or 0.01 percent, at 1,692.48. The Nasdaq Composite Index was up 14.72 points, or 0.41 percent, at 3,593.74.
On Tuesday the S&P 500 snapped a four-day winning streak and pulled back from Monday's record closing high, while healthy earnings from United Technologies gave the Dow a slight lift.
In another busy day of earnings, Caterpillar Inc reported a lower quarterly profit and cut its outlook for full-year earnings, saying its independent dealers were focused on reducing machine inventories rather than building them up. The stock fell 2.5 percent to $83.34.
A&T Inc posted a quarterly profit late Tuesday that missed Wall Street expectations as it was hit by rising costs. The stock was off 2.3 percent at $35.01.
But Boeing Co, also Dow component, posted better-than-expected second-quarter results, helped by a 15 percent jump in commercial aircraft revenue. The stock rose 0.4 percent to $108.16 in premarket trade.
Overseas, euro zone private industry unexpectedly bounced back to show growth this month as factories increased output for the first time in well over a year, according to business surveys. The unexpected rise in euro zone economic activity sparked a rally in European shares.
But a sign of China's economy was slowing cast a cloud over the positive news out of Europe. China's flash HSBC/Markit Purchasing Managers' Index fell as new orders faltered and a sub-index measuring employment sank to its weakest since March 2009. Asian stocks fell after the economic indicators from China.