Microsoft makes an unsolicited offer for its competitior, Yahoo, after shares of the company's stock price tanked 50% since October.

I'm Mathew Karnitschnig, the Mergers & Acquisitions reporter for the Wall Street Journal.

This morning, Microsoft unveiled an unsolicited 45-billion-dollar offer to acquire Yahoo. The deal has been rumored for months. But Yahoo's stock price has fallen about 50 percent since October. And Microsoft has finally decided to pounce. About a year ago, Microsoft made an initial approach to Yahoo, and at the time, Yahoo said that it wasn't interested in pursuing a deal. But its own business has hit headwinds as it recently described in its quarterly earnings report.

And Microsoft, as well, has been looking over its shoulder at Google. Google controls a large portion of the online advertising market. And both Yahoo and Microsoft are concerned about Google's dominance in this, in this area. Another concern of Microsoft is that Google is getting into some of its traditional sectors, including word processing and other applications that have really made Microsoft what it is and is putting those online and free to anybody who, who has an Internet connection. So all of these forces together have prompted Microsoft to act today. The question is will Yahoo which has typically taken a rather skeptical approach towards Microsoft be willing to accept this? The CEO of Yahoo, Jerry Yang has been a long-time enemy of Microsoft and it's unlikely that he's going to want to accept this deal.

This is Mathew Karnitschnig for the Wall Street Journal.