Amid a global slump in personal computer sales, Hewlett-Packard (HPQ) has relinquished its position as the world’s biggest PC seller for the first time in five years, one research firm reported Wednesday, while another had the Palo Alto technology giant clinging to the top spot.

The bad news for HP was compounded by an additional report Wednesday that PC shipments from computer makers for the year would likely shrink about 1 percent, with the last such drop recorded during the dot-com bust of 2001.

“HP has given up the PC vendor position for the first time since the third quarter of 2006,” according to the market monitoring firm Gartner. It said the top position for the quarter was held by Lenovo of China, which previously had been in second place.

Lenovo edged out HP with 15.7 percent of the 87.5 million PC shipments for the quarter, a nearly 10 percent increase for the Beijing-based company over the same period a year ago. HP’s 15.5 percent share represented a drop of 16.4 percent from the third quarter last year, Gartner said.

Another research firm — International Data Corporation — reported that HP still held a narrow lead in the top position, with 15.9 percent of the market, while Lenovo held 15.7 percent. However, its data also showed HP fast losing ground to Lenovo.

Asked to respond, HP spokesman Michael Thacker noted that, “while there are a variety of PC share reports in the market, some don’t measure the market in its entirety. The IDC analysis includes the very important workstation segment and, therefore, is more comprehensive.”

Nonetheless, both reports contained troublesome news for HP, as well as for Santa Clara-based Intel (INTC), which gets most of its revenue by providing microchips to PCs and which counts on HP as its biggest customer.

Gartner said worldwide PC shipments from computer makers declined 8 percent in the third quarter, while International Data Corporation estimated the drop at 8.6 percent.

“PCs are going through a severe slump,” said IDC senior research analyst Jay Chou, in a prepared statement. “The industry had already weathered a rough second quarter, and now the third quarter was even worse.”

Research firm IHS offered a similarly gloomy assessment for 2012 as a whole. It projected PC shipments to shrivel by 1.2 percent to 348.7 million units, down from 352.8 million in 2011.

“There was great hope through the first half that 2012 would prove to be a rebound year for the PC market,” said IHS principal analyst Craig Stice in a prepared statement. But now, he added, “optimism has vanished and turned to doubt, and the industry is now training its sights on 2013 to deliver the hoped-for rebound. All this is setting the PC market up for its first annual decline since the dot-com bust year of 2001.”

Contact Steve Johnson at sjohnson@mercurynews.com or 408-920-5043. Follow him at Twitter.com/steveatmercnews