本研究以1997 至2005 年期間台灣非金融業之上市櫃公司為樣本，探討權益市值高估是否會衍生額外的盈餘管理誘因以及經理人權益誘因是否會使權益市值高估所衍生之盈餘管理更趨嚴重。實證結果發現，前一年度權益市值高估相較於權益市值未高估公司，其當年度異常應計數較大。再者，對於權益市值高估公司，若經理人之權益誘因愈高，則其異常應計數愈大。此外，若經理人權益誘因愈高或正向異常應計數愈大，則其經理人在未來一年內大額出售持股之可能性愈高，且權益市值高估相較於權益市值未高估公司，權益誘因及盈餘管理與經理人在未來一年內大額出售持股可能性之關聯性較高。本研究之實證結果支持Jensen (2005)「權益市值高估之代理成本」假說，並提供了權益市值高估兩種代理成本之證據─盈餘管理與內部人交易，發現當權益市值高估時，提高權益誘因非但無法調和所有權與經營權分離之代理衝突，反而會使盈餘操縱與內部人交易更趨嚴重，導致更高之代理成本。

This study investigates the empirical implications of the agency theory of overvalued equity(Jensen, 2005). It finds that after controlling for other earnings management incentives, firms with overvalued equity have larger abnormal accruals than non-overvalued firms. Besides, equity incentives provided for managers of overvalued firms exacerbate opportunistic earnings management. I also find that managers with higher equity incentives or undertaking more aggressive earnings management are more likely to take large share selling in the following year and that effects are more pronounced for overvalued firms. This study provides empirical support for the agency theory of overvalued equity (Jensen, 2005), as Jensen said, "Equity-based compensation cannot solve the problem because it makes the problem worse, not better (for overvalued firms)".