This study examines whether mutual fund managers generate alpha through thematic investment strategies that select stocks poised to benefit from specific themes. Using textual analysis of 10-K filings, we identify stocks’ thematic exposures and construct each fund’s thematic concentration index (TCI) from its holdings. High-TCI funds significantly outperform, with a top-minus-bottom decile spread of 4.26% in annualized four-factor alpha. Managers’ thematic expertise is related to their undergraduate field of study. Outperformance arises from superior stock selection rather than theme-related timing, with an informational advantage on firm earnings, particularly in stocks exposed to themes related to managers’ undergraduate training.

We find that mutual funds holding a larger concentration of high gross profitability stocks generate better future performance. The outperformance of these funds is not driven by a profitability-related risk premium and is not a byproduct of fund managers’ exploitation of other well-known investment strategies. We show that fund managers who trade on the gross profitability anomaly possess greater skill and create value by attracting future fund inflows and by growing fund assets under management. We contribute to both the mutual fund and market anomaly literatures by providing strong evidence that a sizable subset of mutual fund managers profit from an important market anomaly.