IBM is in talks to buy Sun Microsystems in multi-billion dollar a deal that would expand its server market share, according to a Wall Street Journal report this morning.

IBM may pay as much as $6.5bn in cash for Sun, the newspaper reported on its website, without naming its sources. That amount of money would be nearly double Sun's closing share price on Tuesday of $4.97 per share.

The report cautioned that while the two companies are holding discussions, a transaction may not occur.

The Wall Street Journal said the deal would help IBM tackle new rival, Cisco, which announced it would start selling a server of its own earlier this week.