Can Mutual Fund Stars Still Pick Stocks?: A Replication and Extension of Kosowski, Timmermann, Wermers, and White (2006) 

Kosowski et al. (2006) use a novel bootstrap technique to study the performance of domestic equity mutual funds over the period 1975 to 2002. They find that “a sizable minority of managers pick stocks well enough to more than cover their costs.” When replicating their analysis during their period of study, I find results similar to theirs. However, if I perform an identical analysis over the period 2003 to 2017, I find no evidence of stock selection ability in excess of costs. Furthermore, the combined 1975 to 2017 period indicates that the alphas of the best funds likely occur solely due to luck.