公司管理者乃因減緩與投資人間資訊不對稱可帶來減少資金成本的好處，因此有意圖透過自願性揭露的方式以減緩資訊不對稱。然，自願性揭露方式很多，其中又以法人說明會的召開與自願性盈餘預測的發布為管理者及投資人所重視，因此本研究欲探討法說會與自願性盈餘預測對減緩資訊不對稱的效果及此兩種自願性揭露工具間的關係。 實證結果顯示，法說會與自願性盈餘預測皆能減緩資訊不對稱，且法說會較自願性盈餘預測在減緩資訊不對稱上更具效果。 本研究亦欲探討法說會與自願性盈餘預測間之關係，根據兩階段最小平方法（two stage least squares (2SLS) estimator）的結果顯示此兩種自願性揭露工具的確存在替代關係，亦即管理者並不傾向同時使用法說會與自願性盈餘預測以減緩資訊不對稱。又，資訊複雜度低的公司，法說會與自願性盈餘預測則仍具替代關係；但資訊複雜度高的公司法說會與自願性盈餘預測則不具替代關係。此即表示，資訊複雜度較高的公司管理者可能願意同時使用法人說明會與自願性盈餘預測，但資訊複雜度較低的公司，管理者則不樂於同時使用此兩種工具減緩資訊不對稱。 Since managers can lower cost of capital by reduce information asymmetry between managers and investors, they have motivation to mitigate information asymmetry through voluntary disclosures. However, managers and investors pay more attention on conference calls and voluntary earnings forecasts than other voluntary disclosures, so this research would like to compare conference calls with voluntary earnings forecasts toward information asymmetry and examines the relationship between conference calls and voluntary earnings forecasts. This study presents evidence that conference calls and voluntary earnings forecasts will mitigate information asymmetry. Further, conference call will have better effect than voluntary earnings forecasts. Moreover, this study examine the relationship between conference calls and voluntary earnings forecasts. Base on two stage least squares (2SLS) estimator, This paper observe substitute effect between these two voluntary disclosure instruments. The result supports the argument that conference calls and voluntary earnings forecasts can not help mitigate information asymmetry simultaneously. This paper also observe evidence of substitute effect between conference calls and voluntary earnings forecasts when companies have less complicated information, but this paper doesn’t observe evidence when companies have more complicated information. It means that managers may use conference calls and voluntary earnings forecasts simultaneously to mitigate information asymmetry when they have more complicated information, but they are not willing to do so when they have less complicated information.
