We analyze information disclosure by mutual funds when investors learn from strategy descriptions in fund prospectuses as well as performance. We show theoretically that fund managers with specialized strategies optimally choose to disclose detailed descriptions, while managers with standardized strategies provide generic descriptions. Generic prospectuses lead to errors in benchmark inference, which induce to higher volatility in capital flows. While all fund managers dislike such volatility, those with above-average factor exposures also benefit from benchmarking errors as investors in-correctly ascribe factor returns to managerial skill. The model generates a number of predictions that we are able to test empirically, using a comprehensive dataset of fund prospectuses. Consistent with the model's predictions, we nd that funds with standardized strategies include more boilerplate in their prospectuses, grow larger and have lower ow-performance sensitivity, despite having greater fund flow volatility.