ZeniMax, the parent holding company of Bethesda Softworks/Bethesda Games, bought iD in 2009.[1] Microsoft bought ZeniMax for $7.5B in 2020 and assigned it to the Xbox division.[2] ZeniMax's board was subsequently dissolved, so it's entirely Microsoft.[3]

1: https://www.gamedeveloper.com/game-platforms/bethesda-parent...

2: https://news.xbox.com/en-us/2020/09/21/welcoming-bethesda-to...

3: https://www.gamespot.com/articles/zenimax-board-of-directors...