@jamesmarshall @rbreich

It really depends on how demand works. How likely is a third party to decide they have enough exposure to some company? Is there an upper limit to the number of shares someone wants to buy of company X?

And I sort of assume so?

Also since it's mostly rich people buying the large batches of stocks a wealth tax would also force the rich people buying other companies to sell off some of their stock.

Admittedly spreading ownership of companies out more would probably be more democratic. A bunch of twitter's (or facebooks) problems are because there's no one who can check the owner (or CEO) who controls the majority of the voting shares.