本研究將強制性揭露對自願性揭露之影響納入Nagar（1999）的模型中，以分析自願性揭露均衡。本研究同時考量強制性揭露對於投資人資訊搜尋的效果，以及強制性揭露提供經理人自願性揭露誘因的作用。本研究發現：相較於Nagar（1999）的模型，經理人有更強的誘因將其私有資訊揭露給資本市場，故揭露代理問題在雙揭露制交互作用下較只考量自願性揭露制為不嚴重。此外，本研究的模型產生另一異於Nagar模型的揭露均衡：當投資人沒有私有資訊時，自願性揭露之自發效果與強制性揭露對於自願性揭露之誘發效果的共同運作下，並不存在充分自願性揭露均衡。最後，自願性揭露之可能性與強制性揭露的資訊品質、自願性揭露的資訊品質之間，均呈現正相關。因此，本研究對於盈餘揭露管制，以及建立良好會計系統以提供經理人公司資產資訊兩方面，具有政策意涵。

This paper analyzes voluntary disclosure equilibria by modifying Nagar's (1999) model and including the effect of mandatory disclosures on his model. We consider mandatory disclosures' effect in triggering investors' information search and in motivating managers to make voluntary disclosures. Our extended model demonstrates that managers have more incentives to disclose private information to the capital market than Nagar's model indicates, which means the managerial disclosure agency problem is mitigated by the interaction between mandatory and voluntary disclosures. Moreover, our model yields additional disclosure equilibria that differ significantly from the equilibria in Nagar (1999): incorporating both self-effect and induced effect on the voluntary disclosure strategy rules out a full-disclosure equilibrium when the investors have no private information. Finally, the likelihood that managers will provide voluntary disclosures is positively related to the quality of both the mandatory and voluntary disclosures. Therefore, this study has policy implications in view of recent calls for regulating the disclosures in press releases related to earnings and setting up good accounting systems that provide managers with more appropriate measures of firm-specific assets.