The European Commission on Monday said it has opened probes into two acquisitions in the computer hard-disk sector.

The first is Seagate Technology Inc.'s (STX) plan to buy the hard disk drive business of Samsung Electronics Co. (SSNHY, 005930.SE), and the second is the purchase of Hitachi Ltd.'s (HIT, 6501.TO) hard-disk business by Western Digital Corp (WDC).

"Hard drives are the backbone of the digital economy. The sector has already experienced significant consolidation, and the proposed acquisitions will further reduce competition," said E.U. antitrust commissioner Joaquin Almunia in a statement. "The commission will carefully examine if effective competition is preserved and innovation encouraged."

The commission said the merged companies would have significant share in the market for 3.5-inch hard drives, used in desktop computers, and the market for 2.5-inch hard drives, used in mobile devices.

-By Matthew Dalton, Dow Jones Newswires; +32 (0)2 741 1487; matthew.dalton@dowjones.com