We investigate the portfolio choices of mean-variance-optimizing investors who use sample evidence to update prior beliefs centered on either risk-based or characteristic-based pricing models. With dogmatic beliefs in such models and an unconstrained ratio of position size to capital, optimal...

We analyze the equilibrium size of the active management industry and the role of historical data - how investors use it to decide how much to invest in the industry, and how researchers use it to judge whether the industry's size is reasonable. As the industry's size increases, every manager's...

Extremely long odds accompany the chance that spurious-regression bias accounts for investor sentiment's observed role in stock-return anomalies. We replace investor sentiment with a simulated persistent series in regressions reported by Stambaugh, Yu and Yuan (2012), who find higher long-short...

We argue that active management's popularity is not puzzling despite the industry's poor track record. Our explanation features decreasing returns to scale: As the industry's size increases, every manager's ability to outperform passive benchmarks declines. The poor track record occurred before...

Extremely long odds accompany the chance that spurious-regression bias accounts for investor sentiment's observed role in stock-return anomalies. We replace investor sentiment with a simulated persistent series in regressions reported by Stambaugh, Yu and Yuan (2012), who find higher long-short...

"We analyze the equilibrium size of the active management industry and the role of historical data--how investors use it to decide how much to invest in the industry, and how researchers use it to judge whether the industry's size is reasonable. As the industry's size increases, every manager's...