This paper derives the relationship between a stock's beta and its weighting in the portfolio against which its beta is calculated. Contrary to intuition the effect of this market weight is in general very substantial. We then suggest an alternative to the conventional measure of abnormal...

This paper examines the relationship between the market weight of a single stock and the betas of both that stock and the residual portfolio. Theory suggests that the effect of such a large weight is to significantly reduce the beta of the residual portfolio, and it may also significantly raise...