Mac Market Share Surges in U.S.

Preliminary estimates by Gartner (s it) and IDC put U.S. Mac (s aapl) market share for third quarter 2010 at 9.3 percent and 10.6 percent respectively. Both firms report double-digit growth for the Mac in the U.S. year over year, 13.7 percent from Gartner and 24.1 percent from IDC, compared to a range of two to four percent on average for the industry.

It appears that blistering sales of the iPad, estimated at approximately two million units per month, have not resulted in Mac cannibalization. According to IDC VP Bob O’Donnell, the iPad has negatively impacted the netbook market, but “the halo effect of the device also helped propel Mac sales.” IDC has Acer’s growth as flat for the quarter in the U.S., but Gartner reports a whopping decline of 24 percent for the netbook maker’s U.S. market share. Both research firms have Dell (s dell) down between four and five percent.

Although now the number three PC maker in the U.S., Apple has yet to appear in the top five worldwide. The fifth position is currently held by Toshiba, which sold approximately 4.7 million PCs for the third quarter, compared to 3.47 million Macs. Apple could overtake Toshiba next year if estimates are correct.

Looking at Mac market share in the U.S. over the last five years shows just how much has changed for Apple. In the third quarter of 2005, Apple sold 1.182 million Macs worldwide; 595,000 in the Americas. Gartner estimates 1.831 million Macs were sold in the U.S. for third quarter 2010. That’s a change in market share from 4.6 to 10.4 percent in five years.

While that’s impressive growth, over the last five years the percentage of Macs sold in the U.S. has actually declined relative to international growth, from 50 percent of sales for third quarter 2005 to 40 percent for third quarter 2010. What that means is that as fast as Mac sales are growing in the U.S, they are growing even faster internationally.

It’s been nearly 20 years since the Mac last had a double-digit share of the U.S. PC market, but the next 10 years could see the Mac attain a share of worldwide sales that no one ever imagined.

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