That can only be the case if people are moving money from other assets into stocks because of index funds. Maybe that's happening (less CDs perhaps?) but the ar

That can only be the case if people are moving money from other assets into stocks because of index funds. Maybe that's happening (less CDs perhaps?) but the argument for indexing is much more "stop buying expensive managed stock funds and use much cheaper stock index funds". And that shouldn't create a bubble in stocks because there is no more capital invested in total.