> > When an index fund investor sells, they’re technically selling their holdings in direct proportion to their weighting in the index. So there is literally no market impact.

Yeah, I wanted to highlight that that's not true. Of course there is a market impact, it'll go down. The author might have wanted to say that there is no differential market impact, ie all shares would go down to the same extent (so that there is no impact, say, on capital allocation), but even that is not necessarily true, it clearly depends on the homogeneity (or lack thereof) of the liquidity/elasticity on the other side of those trades.