** Roza, M., Celio, M. B., Harvey, J., Wishon, S. (2003) A matter of definition: Is there truly a shortage of principals? (cacollaborative.org)
I feel like indexing can't really produce bubbles on its own, as a matter of definition, but perhaps you could tell a story like: As skeptical money moves to index funds, active management makes up a smaller and more credulous portion of the market, leading to bubbles in individual stocks that the passive money has no power to correct. (bloomberg.com)
This, I take it, is a matter of definition. (firstthings.com)