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halo seemed a little more distinct on Tuesday following two reports that highlighted market-share gains for the company's computers.

Second-quarter sales of Macintosh computers grew faster than the market according to two separate reports released late Monday. The results, which confirmed comments made by company management last week, marked the third straight quarter of share gains for the company.

The gains are further evidence that the so-called halo effect is real, said Gene Munster, an analyst with Piper Jaffray, in a research note on Tuesday. Analysts such as Munster have predicted that the popularity of Apple's iPod digital music players would draw in new customers for Apple's Macintosh computers.

"We expect continued market-share gains through the back-half of

this calendar year, as Apple benefits from carryover from the massive installed base of iPods during the back-to-school and holiday seasons," said Munster, whose firm has not done recent investment banking business with Apple.

Apple's shares seemed to benefit from the market-share news and from Munster's report. In recent trading, the stock was up $1.16, or 2.8%, to $42.65.

In the second quarter, Apple shipped 658,000 computers in the United States, according to IDC. That amount was up 33% from the same period a year earlier, nearly triple the 11.7% rate at which the overall U.S. PC market grew. For the quarter, Apple's share stood at 4.5% of the market, up from 3.7% a year earlier and placing it fourth among the top PC makers in the U.S.

Apple's share of the U.S. market has grown by about 60% since hitting its recent nadir of about 2.8% in the first quarter of last year.

Worldwide, Apple's shipments grew by 37%, according to IDC. In contrast, the overall PC market grew by 16.6% worldwide.

IDC's numbers paralleled

those from Gartner, which also were released Monday. According to Gartner, Apple's U.S. computer shipments grew 31% in the second quarter, the fastest rate among domestic competitors and propelling the company into fourth place among market-share leaders.

Last week, Apple

reported a blowout quarter, thanks in part to strong sales of its Macintosh line.


plans to replace the PowerPC chips at the heart of the Macintosh computers with chips from


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beginning next year. Some analysts have

predicted that the chip transition could slow the company's computer sales.

Apple officials said last week that they had seen no evidence of a sales slowdown due to the transition. However, they offered cautious guidance for the coming quarter, saying that the changeover to Intel chips could indeed affect sales.