They do because their promise is to match the index, not produce better returns.
Moreover, S&P500 is cap-weighted so even besides membership changes it is rebalanced (the weights of different stocks in the portfolio change) on a regular basis. That also leads to rather predictable trades by the indexers.
They do because their promise is to match the index, not produce better returns.
Moreover, S&P500 is cap-weighted so even besides membership changes it is rebalanced (the weights of different stocks in the portfolio change) on a regular basis. That also leads to rather predictable trades by the indexers.