By Billy Crosby

Worldwide shipments of tablets rose 60% in the second quarter from a year earlier, despite no new products being released by any of the major tech companies, while volumes slowed sequentially, according to industry watcher International Data Corp.

For the latest quarter, 45.1 million units were shipped in total, up from 28.3 million a year earlier, but down from 49.2 million in the previous quarter.

Shipments of Apple Inc.'s (AAPL) iPad fell 14% from the year earlier to 14.6 million, below the research company's predictions. In previous years, Apple has released a new tablet in the second quarter, but this year, the company is expected to launch new tablet products in the second half of the year, IDC said.

"With no new iPads, the market slowed for many vendors, and that's likely to continue into the third quarter. However, by the fourth quarter we expect new products from Apple, Amazon, and others to drive impressive growth in the market," said research director Tom Mainelli.

Apple's market share decreased to 32.4%, compared with 60.3% a year ago.

"Apple aside, the remaining vendors are still very much figuring out which platform strategy will be successful over the long run," said Ryan Reith, program manager for IDC's mobility tracker programs. "To date, Android has been far more successful than the Windows 8 platform. However, Microsoft-fueled products are starting to make notable progress into the market."

In second place, Samsung Electronics Co. (SSNHY) saw shipments almost triple, shipping 8.1 million units compared with 2.1 million a year earlier, to grab 16% of the market--up from 7.6% last year.

No. 3 ASUSTeK Computer Inc. (ASUS) shipped 2 million units, more than doubling its shipments from last year to grab 4.5% of the market share.

PC stalwarts Lenovo Group Ltd. and Acer Inc. both re-entered the top five this quarter.

Lenovo shipped more than double what it did last year to 1.5 million units to grab 3.3% of the market. Acer's shipments also more than doubled to 1.4 million to grab a 3.1% market share.

Microsoft Corp. (MSFT) failed to make the top five.

Write to Billy Crosby at William.Crosby@wsj.com

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