Managerial incentives are substantially related to a firm's market value, so how information is revealed to the market affects managerial behavior. We analyze a model in which the manager needs to exert costly effort to implement a risky, long-term project and the project may generate verifiable information revealing its value. The optimal disclosure rule to motivate managerial effort is the manager's strategic disclosure because it protects the manager from the downside of the project and induces the rational market to punish nondisclosure. A more transparent information regime is not always preferred because it may reduce the manager's discretion over disclosure. We also derive the optimal disclosure when both effort stimulation and project selection are considered.