Patent licensing fees. Microsoft holds a number of patents that they developed or purchased like exFAT and Exchange ActiveSync that are in every Android device made recently.<p><a href="http:&#x2F;&#x2F;arstechnica.com&#x2F;tech-policy&#x2F;2014&#x2F;06&#x2F;chinese-govt-reveals-microsofts-secret-list-of-android-killer-patents&#x2F;" rel="nofollow">http:&#x2F;&#x2F;arstechnica.com&#x2F;tech-policy&#x2F;2014&#x2F;06&#x2F;chinese-govt-reve...</a>