Thematic Concentration and Mutual Fund Performance

Abstract

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.