Rumours of a potential Google/Youtube buyout of Twitch were circling, with the figure settling at somewhere around $1 billion, but according to a Verge report there were plenty of other potential suitors, including Microsoft.
The Verge is claiming that one source claimed that Microsoft had made a serious bid for Twitch, but felt as though YouTube and Google were a safer bet in terms of taking the Twitch service mainstream. The source claimed that had Microsoft made a similar bid, it most likely would have been rejected.
It's an interesting one. Some sort of exclusivity with the Xbox One would most likely have been a lynchpin of any deal with Microsoft and Twitch is already well established on the PS4. That would have been a bit of a stumbling block to begin with.