Although surging tablet sales are eating into sales of more expensive computers and netbooks, the Mac market share continues to throw, thanks to products like the best-selling MacBook Air.

In fact, the Mac line of products accounts for 17% of the $420 price estimate for Apple stock by “Seeking Alpha” (, while iPads represent an additional 7%. The price estimate by the “website for actionable stock market opinion and analysis, and vibrant, intelligent finance discussion” stands about 15% ahead of market price.

“Seeking Alpha” says its report revised 2011 computer growth rate expectations from 15.9% to 10.5% for 2011, as the iPad and other tablets continue to cannibalize computer sales. However, SA expects Apple to offset this trend with notable market share gains in both notebooks and desktops. Apple’s share in the notebook market has increased from around 3.5% in 2005 to 4.8% in 2010, and SA anticipates further gains beyond 6% by the end of their forecast period.

“Although tablets are believed to have cannibalized a good chunk of PC sales, Apple’s Mac sales have actually maintained a solid growth pace,” says “Seeking Alpha.” “Rather than cannibalizing Apple’s own product sales, the iPad appears to be creating a halo effect and lifting sales for the company’s other product.”