Index rebalancing and stock market composition: Do indexes time the market?

Value-weighted indexes must rebalance in response to stock market composition changes, e.g., issuance, buybacks, and IPOs. In doing so, existing index funds implicitly engage in market timing. Index funds’ long-short rebalancing portfolios have an annualized return of 4.61% and load negatively on value and profitability factors. We estimate these trades impose a 46–69 bps annual index-level performance drag. We explore alternative value-weighted indexes that rebalance less and delay responding t