time with 15.7 percent of the market in the third quarter of 2012, edging HP with 15.5 percent.
Gartner pointed out that Lenovo has used "aggressive" pricing, especially in the professional market and has boosted its market share across all regions even as PC sales weaken.
Gartner said worldwide PC shipments totaled 87.5 million units in the quarter, a sharp decline of 8.3 percent from a year ago, as many retailers and consumers held back for the new Windows 8 PCs due in late October.
Mikako Kitagawa, analyst at Gartner, said, "Retailers were conservative in placing orders as they responded to weak back-to-school sales. By the end of September, retailers were focused on clearing out inventory in advance of the Windows 8 launch later this month."
Gartner said Dell was the number three maker with a 10.5 percent global market share followed by Taiwan's Acer with 9.8 percent and another Taiwan firm Asus with 7.3 percent.
In the US market, HP remained the largest maker, followed by Dell, Apple and Lenovo in that order.
A separate report showed global sales of personal computers are set to show a decline for the first time in 11 years.
The survey by IHS iSuppli said the total PC market in 2012 is expected to contract by 1.2 percent to 348.7 million units, down from 352.8 million in 2011.
That would be the first drop since 2001, but sales have been sluggish for the past two years.
"There was great hope through the first half that 2012 would prove to be a rebound year for the PC market," said Craig Stice, an IHS analyst.
"Now three-quarters through the year, the usual boost from the back-to-school season appears to be a bust, and both AMD's and Intel's third-quarter outlooks appear to be flat to down."
IHS said a strong rebound could still occur in 2013, with more adoption of Windows 8 computers and newer, thinner notebook computers gaining tracking.
"Whether a newly configured PC space could then stand up to the powerful smartphone and tablet markets, however, remains to be seen," IHS said.
Analysts say PCs have taken a back seat to tablets and smartphones in recent months.
IHS said last month that global sales of tablet computers are expected to surge to 126.6 million in 2012, driven by the iPad and rivals.
Some analysts say tablet sales will overtake that of PCs by 2016, or possibly earlier.