IDC anticipates that HP will reclaim its top spot before the end of the year, after slipping to third place during the second quarter.
Speaking to CRN, IDC research manager Eszter Morvay said that Acer in particular will struggle to stay ahead of HP, especially once corporate sales begin to recover.
"Acer's performance is so strong in the consumer space and they have also always been very strong in the SME area, where they have deployed aggressive pricing," she told the magazine.
"But it does not have a footprint in the corporate space. Once the economic climate is better and the renewal cycle starts we will see different results for HP and Lenovo. Dell and HP cover the whole market, but Acer's market level will be capped."
Morvay added that HP's displacement is a wider symptom of the current volatility of the market. She pointed to the example of Asus, which at its height was a common name in the top-five laptop vendors, but is now languishing at ninth in the UK market.
According to Morvay, the company had overstretched itself, struggling with inventory and an unanticipated number of competitors. "Two key areas have really hurt Asus: it has been battling with inventory on the one hand and competition on the other. It has had some inventory issues, including a major deal with Carphone Warehouse, which burned its fingers.
She added that while it has been the pioneer of the sector, it had failed to maintain that momentum. "It may have invented the netbook category, but Acer and Samsung have launched major pushes."