We show theoretically and empirically that flows into index funds raise the prices of large stocks in the index disproportionately more than the prices of small stocks. Conversely, flows predict a high future return of the small-minus-large index portfolio. This finding runs counter to the CAPM,...

We show theoretically and empirically that flows into index funds raise the prices of large stocks in the index disproportionately more than the prices of small stocks. Conversely, flows predict a high future return of the small-minus-large index portfolio. This finding runs counter to the CAPM,...