Acer unseated Toshiba from its third-place perch in worldwide mobile PC sales during the fourth quarter of last year, according to market researcher iSuppli. HP saw the strongest year-on-year growth overall in the segment.

The market researcher is the first to confirm Acer's step up in the PC rankings, although it is just in mobile PCs, a segment mainly composed of laptops. Last month, an IDC analyst predicted Acer could slingshot ahead of rival Lenovo Group to become the world's third-largest PC vendor overall during the first quarter of this year.

Acer has come on strong in recent years, growing shipments at a faster clip than its rivals due to a focus on laptop PC sales and a business model that rewards distributors and other partners as Acer sells more.

The Taiwanese company sold 3.37 million mobile PCs in the fourth quarter of 2006, handily beating Toshiba, which sold 2.45 million of the devices, iSuppli said. Its strong 46% year-on-year growth put Acer in reach of Dell, which saw its sales in the period rise just 4.2% to 3.52 million units.

HP retained its lead in mobile PCs with the best year-on-year growth of any vendor, 52%, to reach sales of 5.05 million units. The company was also named the largest PC vendor overall in the fourth quarter of last year by IDC. And there are indications that it has taken note of Acer's speedy rise.

Last week, the company filed a lawsuit against Acer alleging infringement of several patents related to PCs, but analysts largely see the move as an attempt to slow down Acer's expansion.

Acer has been continuously growing its PC shipments and gaining market share in various markets, particularly in notebooks, making it "a threat that leading PC vendors cannot afford to neglect," said Henry King, an analyst for Goldman Sachs (Asia), in a report. He believes Acer is protected in the patent case by cross-licenses held by PC contract manufacturers, which produce computers for all of the major PC vendors.

The IDG News Service is a Network World affiliate.