After the merger Xbox potentially have over half a billion unique monthly active users. Figures shown in post.

So these are the last official figures announced for various Xbox (Microsoft gaming) owned divisions (Monthly active users):

Xbox - 120 million

Activision/Blizzard - 356 million

King - 238 million

Minecraft - 166 million

Those figures accumulated would equal a staggering 880 million monthly active users. That's getting very close to 1 billion, however...

Obviously there is going to be overlap in regards to these numbers, Many Activision users will also be Xbox users and so on. Meaning there absolutely won't be 880 million unique monthly active users in total here.

But I think it's fairly safe to assume that Xbox are very likely hitting around 500+ million unique monthly active users every month across the board.

Also Satya used "over 200 million monthly active users" for Microsoft gaming yesterday, but that was in regards to mobile (Basically king) he then stated they have added "Hundreds of millions" of new users with this merger.