Sony doesn't swoop in and blank check an entire publisher, which Microsoft has now done two times.
Bungie was a shock, but it's still just a developer in the end. They typically fold in studios who have primarily been on PlayStation anyway, which is partly why this one was a surprise.
But Microsoft changed the game entirely with the Activision/Blizzard deal. They've long had the financial power to buy their way into whatever.
I think Square-Enix is the likely purchase, based on prior history and current console exclusives(FF7R,FFXIV, FFXVI upcoming).
Capcom could be, based on EVO being owned by Sony and their exclusivity with Street Fighter V.
There are a few other devs they could have, such as Kojima Productions, Arc System Works, Ember Labs, etc.
But if Sony does go for a big gun, it's most likely Square for me.
But if they do, it'll trigger a consolidation war that will not end well for gamers in the end, I fear.
But one might argue Microsoft already fired those shots.
I remember people feared and postulated 20 years ago,when Microsoft first entered the console gaming sector, that they could just "buy" their way to success if they wanted.
They didn't for a long time, but PlayStation has been market leader for so many generations(save for PS3 I think),I guess they finally decided to pull out the checkbook as many folks figured.