So they have Bill Gates by the balls?
From Merck To Microsoft: These Are The Companies That BlackRock 'Controls' The Most Of
https://www.zerohedge.com/markets/merck-microsoft-these-are-companies-blackrock-controls-most
Discussion
They are not the majority shareholder, in the case of Apple they are the third and in the case of Microsoft they are the second.
But it is enough to have control on the board.