Why Does an Equal-Weighted Portfolio Outperform Value- and Price-Weighted Portfolios?

This paper compares the performance of equal-, value-, and price-weighted portfolios of stocks in the major U.S. equity indices over the last four decades. It finds that the equal-weighted portfolio with monthly rebalancing outperforms the value- and price-weighted portfolios in terms of total mean return, four factor alpha, Sharpe ratio, and certainty-equivalent return, even though the equal-weighted portfolio has greater portfolio risk.