Microsoft's stock has risen after they gave their press conference at E3 2012.
Their stock had closed at around $28.50 on Monday night, but rose to roughly $28.60 on Tuesday night. Their stocks peaked at roughly $29.15 on Wednesday and started Thursday off on a high at $29.70.
This rise, which coincides with their participation at E3 2012, is seen as a sign of confidence from their investors on the announcements made at their press conference on Tuesday where they unveiled new titles for their XBox 360, integrating their motion sensing technology, Kinect, and their controller software which rivals that of Nintendo's new console, Wii U.
Microsoft's stocks are currently $29.22.
Source: http://www.marketwatch.com/investing/stock/msft