Essays on the emiprical properties of stock and mutual fund returns

Abstract

Survivorship bias influences statistical inference in Finance. Through a series of Monte Carlo simulations in the style of Brown, Goetzmann, Ibbotson, and Ross {1992), we study the sampling distribution of the mean return, standard deviation, beta, Fama & MacBeth {1973) t-statistic, and Jegadeesh & Titman (1993) momentum strategy return in progressively truncated datasets. Survivor-biased datasets have higher mean returns, lower return standard deviations and lower betas than the full sample. Beta has no explanatory power even when the CAPM is true, a finding virtually unaffected by survivorship bias. Returns to a momentum strategy are positive even when stock idiosyncratic returns are serially and cross-sectionally uncorrelated, but survivorship bias overestimates the returns and underestimates the beta of the strategy.