Dunno why people are listing the likes of Zenimax or Embracer Group; they are small fry. WB Games is bigger than either of them; WB Games is currently the 5th largest 3rd party video game publisher in the world.
Within the videogame industry, only 3 video game publishers (EA, Take Two, Activision) and two platform holders (Sony, Microsoft), could actually afford them at all.
Otherwise, it would have to be a company from outside the video game industry that really wants a quick and sudden entry point into the western video game market in a major, industry shaking way; and has a mindboggling level of financial backing to not only pay $4+ billion as one time downpayment, but also finance the running costs of the 5th largest video game publisher in the world.
There is only one company that immediately springs to mind; and that company is Tencent. Otherwise? It could be Vivendi; but Tencent simply want it more. This is the big IN into the western market that they have really been waiting for; and they are going to pounce at the chance.