Quantifying Diseconomies Of Scale For Mutual Funds

Abstract

The fund size is highly persistent and correlated with risk factor loadings. Hence, it is unrealistic to assume constant diseconomies of scale over a long time. The traditional two-step method underestimates the uncertainty of diseconomies of scale. We propose a one-step procedure with a random weighted bootstrap method to infer diseconomies of scale using rolling windows, which effectively solves the problems. Our empirical analysis using actively-managed U.S. equity mutual funds supports diseconomies of scale, and simulations show that our rigorous method outperforms the two-step one in terms of precise estimating uncertainty.

Keywords: Diseconomies of scale, fixed effects panel regression, mutual funds

JEL Classification: G23, C58