I would lean towards "no" but on technical grounds. In terms of PR/marketing it would be a great move and if Microsoft's recent moves are any indication it is n

I would lean towards "no" but on technical grounds. In terms of PR/marketing it would be a great move and if Microsoft's recent moves are any indication it is not something behind what the company, today in 2014, would consider. IE is not a stand alone browser. IE is built on top of dozens of different Windows components. In order for IE to be open sourced you would have to open source a large chunk of Windows itself, the two aren't that inseparable. You could definitely open source the UI, but the UI in IE is fairly light weight, most of the actual useful stuff is not within it and providing the UI source would likely not really offer much. Another useful question to ask is, let's say they do open source all of the components, then what? Windows enforces Microsoft signing and other checks on internal components for security reasons. So if you compiled a new copy of e.g. http.sys you likely couldn't install it anyway. Plus they'd have to audit the heck out of the code before doing so for IP issues. It would be very easy for every patent troll to point at lines within IE's code and then sue.