@Storkus:
I think Tissot's statement is the correct one. AS the term "acquired" doesn't explicitly refer to any means of "ownership". It COULD mean "purchased" but it MAY also mean "stolen" "found" or even that you were presented with an item.

But back to the main story.
Could be a number of reasons why they've passed on the patents. Cash-flow problems seem unlikely given that M$ are throwing cash at them.
Maybe they thought 'Patent Trolls? If you can't beat 'em......... join 'em'.