Theoretical models imply fund size and performance should be negatively linked. However, empiricists have failed to uncover consistent support for this negative relation. Using a new econometric framework which includes fund-specific sensitivities to decreasing returns to scale, we find a both...

I document a (within-fund) hump-shaped relation between fund size and subsequent fund performance among U.S. corporate bond mutual funds. When funds are small, they exhibit increasing returns to scale but when they become large, they exhibit decreasing returns to scale. This sharply contrasts...