As can often be the case when a particularly juicy rumour hits trader's ears, what appears to be the very flimsiest of speculation has sent Research in Motion's stock price rising rapidly.

The BlackBerry manufacturer is in the midst of sensational rumours that Microsoft may make a bid for the company.

RIM's stock closed up 91 cents, and over 1.5 million shares were traded in a day that saw the Canadian based company's stock reach a record high of $89.68.

Although it's not clear how the rumours started, it seems that the speculation is as Google are apparently imminently about to launch mobile phone, Microsoft are keen to look into the phone handset market too.

Google recently stepped on Microsoft's toes when the online giant offered Sun's StarOffice as part of their free software offerings.

Unsuprisingly neither RIM nor Microsoft would offer any kind of comment stating that they had a policy of not commenting on speculation.