We empirically analyze the nature of returns to scale in active mutual fund management. We find strong evidence of decreasing returns at the industry level: As the size of the active mutual fund industry increases, a fund's ability to outperform passive benchmarks declines. At the fund level,...

Our framework for evaluating and investing in mutual funds combines observed returns on funds and passive assets with prior beliefs that distinguish pricing-model inaccuracy from managerial skill. A fund's alpha' is defined using passive benchmarks. We show that returns on non-benchmark passive...

This study explores multivariate methods for investment analysis based on a sample of return histories that differ in length across assets. The longer histories provide greater information about moments of returns, not only for the longer-history assets, but for the shorter-history assets as...

We model optimal fund turnover in the presence of time-varying profit opportunities. Our model predicts a positive relation between an active fund's turnover and its subsequent benchmark-adjusted return. We find such a relation for equity mutual funds. This time-series relation between turnover...