By Rex Crum, MarketWatch

SAN FRANCISCO (MarketWatch) -- Tech stocks managed to put in a mostly upbeat market session Tuesday, with Research In Motion Ltd. scoring big gains, but Google Inc. failing to join in the advance ahead of the company's fourth-quarter earnings report, due after the closing bell.

The Nasdaq Composite Index (RIXF) ended the day up by 8.5 points to close at 3,143, while the Philadelphia Semiconductor Index (SOX) fell 0.3% and the Morgan Stanley High Tech 35 Index (MSH) managed a small gain.

RIM (RIMM) shares continued to add to their recent gains, rising 13% to close at $17.90. 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.

Dell (DELL) shares rose 2% to $13.12 by the close, as the latest rumor had Microsoft (MSFT) chipping in to help finance a private-equity buyout of the PC maker. Microsoft's shares were down 0.4%.

Apple (AAPL) shares rose almost 1%, to close at $504.77. 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 rose almost 1% to $42.94. 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 gave up $1.64, to close at $702.87 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.

International Business Machines Corp. (IBM) shares rose almost 1%, to $196.08, while Advanced Micro Devices Inc. (AMD) gave up a penny a share to close at $2.45 and Texas Instruments Inc. (TXN) shed 6 cents a share to end the day at $33.46. All three companies were scheduled to release quarterly reports after Tuesday's market close.

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