Dell Inc is in talks to buy data storage company Compellent Technologies Inc

for $27.50 per share, after losing out to Hewlett-Packard Co in a bidding war for another storage company 3Par.

Compellent shares fell 15 percent in early trade on Thursday as Dell's bid was below its Wednesday closing share price. Compellent shares have risen almost 90 percent since late October when reports emerged about talks between the pair.

Dell said on Thursday the companies entered an exclusive agreement to negotiate a merger in which it would pay $27.50 per share for Compellent, whose shares had closed at $33.65 on New York Stock Exchange Wednesday.

It described the talks with Compellent as advanced discussions but said there could be no assurance they reach a deal. The companies said they do no plan to comment further until an agreement is reached or discussions are ended.

Compellent shares fell to $28.73 in early trade.

(Reporting by Sinead Carew; editing by Derek Caney)