According to Gartner, Apple is the only company increasing market share in the PC market. Worldwide PC shipments are down 0.1 percent, says Gartner.
However while it agrees that PC shipments are down, IDC disagrees that Apple's Mac sales are on the increase.
Gartner analyst Mikako Kitagawa said: "Among the top 5 vendors in the US PC market, all but Apple experienced a decline in shipments."
According to Gartner, Apple shipped 1,910,000 Macs in the second quarter of 2012, up 4.3% on the year before. It gives then 12 per cent of the US market. (The data doesn't include the iPad).
HP shipped 3,976,017 PCs (down 12.7%), and Dell shipped 3,458,736 PCs (down 9.5%).
According to IDC, Apple shifted 1,810,000 Macs in the second quarter of 2012, down 1.1% on 2011. HP was down 12%, on 4,125,000 and Dell sold 3,594,000 PCs (down 9.2%).
IDC's research suggests that it is in fact Lenovo that has grown shipments of PCs, with an increase of 6.1% based on 1,276,000 sales, although, the report notes: "Even Lenovo's growth decelerated abruptly from the double-digit growth rates of previous quarters."
Kitagawa blames the decline on "uncertainties in the economy" as well as "consumer's low interest in PC purchases". He also noted that: "Despite the high expectations for the thin and light notebook segment, Ultrabooks, shipment volume was small and little impact on overall shipment growth."
The IDC report suggest that the decline is due to "disappointing sell-out of distribution channels during the first quarter", noting that there was "limited demand from channels that are wary of building inventory ahead of new product launches this fall". The report also notes that "consumers remained reluctant about purchasing PCs in this environment of tech transition and soft economics".
IDC blames the lack of interest in Ultrabooks on "anticipation of improvements such as Windows 8, which is expected later this year, but also due to pricing."
Finally, IDC notes: "Constrained demand in Europe and the US has also been felt in emerging markets for some time, but the second quarter brought another milestone of sorts as Asia/Pacific (excluding Japan) showed flat year-on-year growth; its worst performance in years."
Sign up for CIO Asia eNewsletters.