Acer Inc. unseated Toshiba Corp. from its third-place spot in worldwide mobile PC sales during the fourth quarter of last year, according to market researcher iSuppli Corp. Hewlett-Packard Co. saw the strongest year-on-year growth and retained first place.
   ISuppli 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 Lenovo Group Ltd. 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 more quickly than its rivals because of a focus on laptop PCs and a business model that rewards distributors and other partners as Acer sells more.
   The Taipei-based 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 Inc., which saw its sales in the period rise just 4.2% to 3.52 million units.
   HP retained its lead with the best year-on-year growth of any vendor, 52%, to reach sales of 5.05 million units. Also, IDC named the company the largest PC vendor overall in the fourth quarter. And there are indications that it has taken note of Acer's speedy rise.
   Last week, HP filed a lawsuit against Acer in the U.S., alleging infringement of several patents related to PCs, but some analysts saw the move as an attempt to slow down Acer's expansion.
   Acer has become "a threat that leading PC vendors cannot afford to neglect," said Henry King, an analyst at Goldman Sachs (Asia) LLC in Taipei, 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 the major PC vendors.