After a strong second quarter, Apple's unit shipment growth slowed in both consumer and commercial (including education) markets, according to an IDC report published Monday.
"We believe a sizeable percentage of consumers interested in buying an Apple tablet sat out the third quarter in anticipation of an announcement about the new iPad Mini," said IDC analyst Tom Mainelli in a statement.
Apple's share sank from 65.5 percent in the second quarter of 2012 to 50.4 percent in the third quarter. In the same period last year, Apple's market share was 59.7 percent.
The other four vendors ranked in the top five all gained share during the quarter. Samsung led the way, buoyed by its Galaxy Tab and Note 10.1, shipping 5.1 million tablets worldwide in the third quarter, up 115 percent from the second quarter of this year. And that's an increase of 325 percent from the third quarter of 2011, when it shipped 1.2 million tablets.
Amazon also made noticeable gains. Amazon, which announced new tablets late in the quarter, saw its worldwide market share from jump from 4.8 percent in the second quarter to 9.0 percent in the third quarter.
Despite all these gains by Apple rivals, it could come roaring back in the fourth quarter. "Now that the new Mini and a fourth-generation full-sized iPad are both shipping we expect Apple to have a very good quarter," IDC said.
And what about Windows 8 and RT tablets that were just announced and don't show up in market share numbers yet? "Price points are critical in tablets, and Microsoft and its partners will have a tough time winning a share of consumer wallet with price points starting at $500," IDC said.
The worldwide tablet market grew 49.5 percent year over year in the third quarter and 6.7 percent over the second quarter of 2012.