We study the information content of the mutual-fund investor mix at the fund level. Building on the fund-flow determinant literature, we develop a method to attribute the proportion of fund net-in-flow explained by a fund’s fundamental characteristics and past performance as smart and dumb money respectively. The fund-level Smart Dumb Ratio (SDR) positively predicts future cross-sectional fund return. A series of tests shows that SDR postively correlates with other skill measures and its effects are enhanced with investor sophistication. Our findings confirm that the investor composition can be a useful source of information to estimate the fund-level smart-money effect.