Actually, you need to know who "controls" Vanguard itself. While mutual funds and ETFs are owned by investors, the voting rights, and thus control, is exercised by Vanguard. Same with Blackrock. So you need to know who controls Vanguard and Blackrock. While those companies have executives, who is on the boards? Who has controlling interest in Blackrock and Vanguard?
People have explored this, and have come to the conclusion that through a complex web of ownership and co-ownership, actual control rests with an old money Plutocracy, which consists of a limited number of interbred families. They think of themselves as royalty, and no doubt they include plenty of old world royalty. It's hidden, and that is intentional. Because of past notoriety, some of those family names are well-known, like Rockefeller, but it is not limited to the better known "conspiracy" names.