This paper provides direct evidence supporting the tax‐loss selling hypothesis as an explanation of the January effect. Examining turn‐of‐the‐year return and volume patterns for municipal bond closed‐end funds, which are held mostly by tax‐sensitive individual investors, we document a January effect for these funds, but not for their underlying assets. We provide evidence that this effect can be largely explained by tax‐loss selling activities at the previous year‐end. Moreover, we find that funds associated with brokerage firms display more tax‐loss selling behavior, suggesting that tax counseling plays a role.

Firms in more concentrated industries earn lower returns, even after controlling for size, book‐to‐market, momentum, and other return determinants. Explanations based on chance, measurement error, capital structure, and persistent in‐sample cash flow shocks do not explain this finding. Drawing on work in industrial organization, we posit that either barriers to entry in highly concentrated industries insulate firms from undiversifiable distress risk, or firms in highly concentrated industries are less risky because they engage in less innovation, and thereby command lower expected returns. Additional time‐series tests support these risk‐based interpretations.