We examine changes in CEOs' disclosure styles in quarterly earnings conference calls over their tenure. Our longitudinal analysis of newly hired CEOs shows that CEOs' forward-looking disclosures and their disclosures' relative optimism decline in their tenure. Further, externally hired and inexperienced CEOs are more future-oriented, and younger CEOs exhibit greater optimism in their disclosures. We also find that non-CEO executives' disclosure styles remain time-invariant over their CEOs' tenure. Our evidence is consistent with uncertainty reduction about managers' ability over their tenure (1) reducing the demand for and the supply of forward-looking disclosures, and (2) attenuating managerial career concerns leading to the decline in disclosure optimism.