Vanguard do still have a lot of control by choosing their investments, because many of the people investing through them are buying blended funds rather than on

Vanguard do still have a lot of control by choosing their investments, because many of the people investing through them are buying blended funds rather than ones invested in a single index. For instance, if you look at funds like the LifeStrategy ones (which you'll commonly see recommended online by people), it's made up of lots of different funds: https://www.vanguardinvestor.co.uk/investments/vanguard-lifestrategy-100-equity-fund-accumulation-shares/portfolio-data https://www.vanguardinvestor.co.uk/investments/vanguard-life... So while they can't easily pick and choose which S&P 500 stocks they include in a fund like that, they can decide if the S&P 500 is 1% or 10% or 50% of what that fund invests in. And given the total amount of investments they have, if they decide to move towards or away from certain countries/indexes/etc that could have a significant impact.