EMC has officially acquired majority ownership of storage vendor Data Domain after a bidding war with NetApp.

After an initial stock purchase offering period ended on Friday, EMC acquired 78.2 per cent of the outstanding Data Domain shares, in addition to the 3.9 per cent of shares previously held by EMC, the company said in a news release.

A second offering period ending on Wednesday will allow Data Domain shareholders to sell their stock at US$33.50 a share, the original price offered by EMC. As of Monday, Data Domain shares were trading at $33.51 on the Nasdaq stock exchange.

Early this month, Data Domain signed a merger agreement with EMC and terminated a previously announced merger deal with NetApp.

Data Domain agreed to a $1.5 billion bid from NetApp on May 20, but EMC countered with an unsolicited offer of $1.8 billion. NetApp raised its bid, but early this month, EMC countered with a $33.50-per-share, $2.1 billion offer.

EMC said it expects to complete the merger and close the acquisition shortly, as long as it controls 90 per cent of the outstanding Data Domain shares.

The company plans to make Data Domain the foundation of a new product division within EMC's storage business. Frank Slootman, Data Domain's president and CEO, will lead that new division.