BlackRock, Vanguard and State Street

Not the most well-known firms in the world but arguably the most powerful.

“These firms manage funds invested by large institutions like pension funds and university endowments as well as those for companies and, in some cases, individual investors like me and perhaps you, too. Their holdings are colossal. BlackRock manages nearly $10 trillion in investments. Vanguard has $8 trillion, and State Street has $4 trillion. Their combined $22 trillion in managed assets is the equivalent of more than half of the combined value of all shares for companies in the S&P 500 (about $38 trillion).

Researchers have argued that this level of concentration will reduce companies’ incentives to compete with one another. This makes a kind of intuitive sense: For example, because Vanguard is the largest shareholder in both Ford and General Motors, why would it benefit from competition between the two? If every company is owned by the same small number of people, why fight as fiercely on prices, innovations and investments?

But if the Big Three keep growing, the effects of their concentrated ownership will get only worse. Einer Elhauge, also of Harvard Law School, has written that concentrated ownership “poses the greatest anticompetitive threat of our time, mainly because it is the one anticompetitive problem we are doing nothing about.”

In late 2018, a few months before his death, John C. Bogle, the founder of Vanguard who developed the first index fund for individual investors, published an extraordinary article in The Wall Street Journal assessing the impact of his life’s work. The index fund had revolutionized Wall Street — but what happens, he wondered, “if it becomes too successful for its own good?” “

https://www.nytimes.com/2022/05/12/opinion/vanguard-power-blackrock-state-street.html 

see also Big 4, Big 5, Big 6 etc