In a testament to its brilliant marketing, innovative packaging, and strong brand image, Apple, Inc. (AAPL) has reportedly achieved over 10 percent U.S. personal computer market share for the first time since the early 1990s.

Both Gartner, Inc. (IT) and IDC Research, Inc. -- two of the most prestigious market research firms -- have concluded [1][2] that Apple took 10.7 of the U.S. market in calendar quarter 2011.  The researchers used gathered shipment data to draw their conclusions, the most accurate of several market analytics approaches.

While the 10 percent figure represents computers sold in the quarter and not the total percentage of computers in operation, the study shows that consumers are increasingly picking Apple, even as the overall PC market struggles.

Incidentally, Apple's best-selling iPad tablet is cited as a major factor in declining PC sales.  Gartner estimates that sales dropped 5.6 percent year-to-year, while the IDC estimates that sales dipped 4.2 percent.  

Gartner analyst Mikako Kitagawa remarks, "Given the hype around media tablets such as the iPad, retailers were very conservative in placing orders for PCs. Instead, they wanted to secure space for media tablets. Some PC vendors had to lower their inventory through promotions, while others slimmed their product lines at retailers."

But Apple managed to buck the trend it helped create, posting 8.5 percent growth, according to Gartner, or 14.7 percent growth according to the IDC.  Both Gartner and the IDC say Apple is now in third place in PC sales.

Another clear "winner" was Japan's Toshiba Corp. (TYO:6502) who rose 3.3 percent according to Gartner, or 3.7 percent according to the IDC.  Toshiba bumped Taiwanese computer-maker ASUSTEK Computer Inc. (TPE:2357) to sixth place in U.S. sales.

Market-leader Hewlett-Packard Company (HPQ) and the Taiwanese Acer Inc. (TPE:2353) shed market share in the U.S.  In Acer's case, the fall was particularly precipitous, with both Gartner and IDC estimating its drop at over 20 percent.  Acer's fall was precipitated by the mild collapse of the netbook market, a key driver of its sales.

Dell, Inc. (DELL) lost ground to HP, dropping 10.2 percent (according to the IDC) or 9.8 percent (according to Gartner), however it still clung to second place.

Global sales showed anemic 2.3 percent growth (Gartner) or 2.6 percent growth (IDC).  HP and Dell both posted similar world growth and enjoyed the same rankings as in the U.S.  Apple did not rank in global sales.  

In global sales ASUSTEK occupied the fifth spot, with Acer's posting a smaller global lost and dropping to fourth.  Globally the biggest winner was Hong Kong-based Lenovo Group, Ltd. (HKG: 0992) who grew 22.9 percent (IDC) or 22.5 percent (Gartner) to seize third place.  Lenovo's biggest gains were in the U.S. and Japan, markets it has traditionally seen lower sales in.

Apple's rise from obscurity to a solid third place ranking in the U.S. is not without its shortcomings.  Apple has thus far struggled to replicate that growth globally, particularly in markets where price trumps image or where local players have a strong foothold (e.g. Asia).  The rise in market share has also led to a rising number of serious malware attacks on Apple's OS X platform -- a platform that has typically been ignored by hackers, thanks to its small market share.