ABSTRACT This paper finds that, for the 1935–1986 period, the market's risk‐return relation does not have a January seasonal. The findings differ from those of other studies due to the use of value‐weighted, rather than equally weighted, portfolios. Inferences are sensitive to the weighting procedure because of the small‐firm return patterns in January. In particular, even in those Januaries for which the market return is negative, small‐firm returns are positive, and they are more positive the higher is beta. This is consistent with the portfolio rebalancing explanation of the turn‐of‐the‐year effect.

This paper finds that, for the 1935–1986 period, the market's risk-return relation does not have a January seasonal. The findings differ from those of other studies due to the use of value-weighted, rather than equally weighted, portfolios. Inferences are sensitive to the weighting procedure because of the small-firm return patterns in January. In particular, even in those Januaries for which the market return is negative, small-firm returns are positive, and they are more positive the higher is beta. This is consistent with the portfolio rebalancing explanation of the turn-of-the-year effect.

A highly controversial issue in financial economies is whether stocks overreact. In this paper we find an economically-important overreaction effect even after adjusting for size and beta. In portfolios formed on the basis of prior five-year returns, extreme prior losers outperform extreme prior winners by 5–10% per year during the subsequent five years. Although we find a pronounced January seasonal, our evidence suggests that the overreaction effect is distinct from tax-loss selling effects. Interestingly, the overreaction effect is substantially stronger for smaller firms than for larger firms. Returns consistent with the overeaction hypothesis are also observed for short windows around quarterly earnings announcements.