Speculation of a potential takeover was published on various blogs and new wire services late last week.

However, many analysts are sceptical that Microsoft would buy a company with such a high valuation: RIM’s market capitalization is about $47bn. Its acquisitions tend to be far smaller. Also Microsoft favours growing its own technologies in house rather than purchase a major company for them.

Still, RIM shares rose more than 3% to close at $85.41 on the Nasdaq Friday. It was the highest price the stock had reached since the company’s three-for-one stock split on August 21. It rose even higher, to $85.49, in after-hours trading.