Mac sales on pace to slide 5% in Apple's September quarter

As the larger PC market continues to struggle, Apple, too, has seen its Mac sales decline year over year — a trend that is on pace to continue in the current September quarter.

The latest data on domestic Mac sales from the NPD Group, detailed on Monday by analyst Gene Munster of Piper Jaffray, suggests that Apple saw flat growth in the month of July, which is the first month of the company's September quarter.

Munster characterized the data as "neutral to slight positive" news for Apple. He has forecast that total worldwide Mac sales for the quarter will be down 5 percent year over year.

Apple sold 3.8 million Macs last quarter, a total that was 200,000 off from the 4 million the company sold in the same period of 2012.

As for the September quarter of 2012, Apple sold 4.9 million Macs during the three-month frame last year, which was then a year over year increase of 9 percent. If Munster's prediction for 2013 proves accurate, Mac sales in the current September quarter would be around 4.65 million.

Mac sales — and the PC market as a whole — are being cannibalized by tablets, and in particular by Apple's market leading iPad lineup.

iPad cannibalization and an oversupply of MacBooks caught Apple executives by surprise earlier this year, AppleInsider revealed earlier this month. That situation is said to have caused the company to adopt a more conservative approach with channel inventory, keeping stock low to avoid another oversupply.

The Mac also plays a relatively minor role in Apple's total business, with the lion's share of revenue now coming from the iPhone and iPad.

Even more diminished is the iPod, as NPD's latest data shows domestic sales of Apple's portable media players down 41 percent year over year in the month of July. Munster has forecast that iPod sales will be down 20 percent year over year in the September quarter.