One week later: Yahoo's effect on Microsoft Share Prices

Microsoft's stocks have been hit by a double whammy; the slow US economy and the non solicited offer the software giant made to Yahoo.

The Redmond-based company lost 13.74 percent of its value in the past seven days, wiping off nearly $36 billion of their market capitalisation.

End of 2007 and beginning of 2008 have been particularly painful for the firm as their share prices went down by 24 percent since the beginning of November 2007.

The sudden, if not expected, drop in Microsoft's stock consequently decreases the value of the Windows and Office developer puts on Yahoo.

The bid is half cash and half stock and Yahoo's shareholders would each receive $28.80 on average, $2.20 less than the $31 initially proposed.

Bottom line, Yahoo is now valued at $41.3 billion, down from $44.6 billion which Wall street insiders (via Reuters) believe, will cause Microsoft to increase its bid price for Yahoo.

This battle for Yahoo could end up costing up much more to stubborn Microsoft.