Why mutual funds "underperform"

I propose a parsimonious model that reproduces the negative risk-adjusted performance of actively managed equity mutual funds. In the model, a fund manager can generate state-dependent active returns at a disutility. Negative expected performance and mutual fund investing simultaneously arise in equilibrium because the active return the fund manager generates covaries positively with a component of the pricing kernel that the performance measure omits, consistent with recent empirical evidence. Using data on U.S. funds, I also document new empirical evidence consistent with the model's cross-sectional implications.