Exploiting the 2009 amendments to Regulation SK, we provide unique evidence on the first-time disclosure of the reasons firms state for combining or separating the roles of CEO and chairman. The stated reasons support both agency theory and organization theory. They are more numerous, comprise more words, and have a more positive tone for firms with duality. Examining the announcement returns to firms' disclosures, we find that investors evaluate the most frequently cited reasons for CEO duality by considering firm's characteristics. Our evidence enhances the understanding of firms' endogenous decision to opt for CEO duality and its value consequences.

Our study is the first to provide systematic evidence of a hump-shaped CEO tenure-firm value relation. Cross-sectionally, firm value starts to decline after fewer years of CEO tenure in more dynamic industries, if CEOs are less adaptable to changes, and in the presence of greater labor market frictions. Overall, the dynamics of CEO-firm match quality appear to be a first-order driver of the CEO tenure-firm value association, as explained by CEO characteristics (adaptability), firm/industry characteristics (dynamism), and labor market characteristics that facilitate optimal matching between firms and CEOs. Data Availability: Data used in this study are available from public sources identified in the study.