By Rex Crum, MarketWatch

SAN FRANCISCO (MarketWatch) -- Tech stocks slipped into the red in early trading Tuesday, with Google Inc. pressuring the sector ahead of its fourth-quarter earnings report, due after the closing bell.

The Nasdaq Composite Index (RIXF) gave up 0.3% to slip to 3,125, while the Philadelphia Semiconductor Index (SOX) fell 0.6% and the Morgan Stanley High Tech 35 Index (MSH) fell by 0.4%.

An early lift from Apple (AAPL) helped the group, but the stock quickly gave back its gains. Verizon (VZ) said it activated 6.2 million iPhones during the fourth quarter of 2012, with almost half of the activations being Apple's iPhone 5.

Brian Marshall, an analyst with ISI Group, said Verizon's report is "a solid number supportive of our estimate of 48 million total iPhones," sold in the December quarter.

But Steven Milunovich of UBS scaled back his price target on Apple to $650 from $700. In his note -- issued prior to Verizon's report -- the analyst cut back his estimated average selling price, or ASP, for the iPhone, citing a survey showing customers opting for lower-memory models of the device.

Verizon (VZ) shares moved up by 0.7% to $42.85. The company reported a loss for the fourth quarter -- hurt in part by high subsidies for the iPhone 5. But the company projected stronger margins for the year, and said on a conference call that it was considering buying back shares.

Google Inc. (GOOG) shares were off by about 1%, at $697.83 in advance of the Internet giant's quarterly results, set for after the close of trading Tuesday. Analysts expect Google to show gains from more of its ad business.

Research In Motion (RIMM) shares climbed more than 10%, to $17.44. RIM Chief Executive Thorsten Heins reiterated to a German newspaper that the company is continuing with a strategic review of all of its business operations -- which could include licensing its software to other handset makers or selling its own handset business.

International Business Machines Corp. (IBM) shares rose fractionally to $195.15, while Advanced Micro Devices Inc. (AMD) was down 0.8% and Texas Instruments Inc. (TXN) shed 0.7%. All three companies are scheduled to release quarterly reports after Tuesday's market close.

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