內部人交易與實質盈餘管理關連性之研究

The Relationship between Insider Trading and Real Earnings Management

證券交易法中將公司的內部人定義為，發行公司之董事、監察人、經理人及持股超過股份總額百分之十股東。過往文獻指出，當企業有財務危機時內部人會有出售本身持股的行為。公司的管理階層具有政策的決策權，並且同時具有資訊優勢，當公司績效不佳時，往往會以盈餘管理來進行掩飾。
本文以台灣上市櫃公司內部人交易月資料為樣本並區分為買入組與賣出組，分別探討兩組內部人交易後的異常報酬與實質盈餘管理的關聯性。研究結果發現當內部人進行買入交易後會產生正的股票異常報酬；而在內部人進行賣出交易後亦產生負的股票異常報酬。然而，有關內部人交易與實質盈餘管理關聯性方面，則是發現買入組的內部人交易與實質盈餘管理並無顯著相關，而賣出組的內部人交易與實質盈餘管理則具有顯著負相關，這表示公司的實質盈餘管理情形越嚴重，其內部人出售股票所可以避免的損失就越大。

The Securities Exchange Act defines the company's insiders as the issuing company's directors, supervisors, managers and the shareholders who holding more than 10% of the total shares. According to previous literature, insiders will sell their own shares in case of financial crisis. The management of the company has the decision-making power of the policy, and at the same time has the information advantage. When the company's performance is not good, it is often covered up with earnings management.
The previous literature also pointed out that when an enterprise has the right to choose, it prefers real earnings management over accrued earnings management. This article uses insider trading month data of Taiwan-listed counter companies as asample and is divided into abuying group and aselling group. The results show that when insiders buy stocks, they generate positive abnormal returns, while when insiders sell stocks, they also generate negative abnormal returns. However, regarding the correlation between insider transactions and real earnings management, it was found that insider transactions in the buying group were not significantly related to real earnings management, while insider transactions in the selling group were significantly negatively related to real earnings management. This means that the more serious the company’s actual earnings management situation, the greater the losses that its insiders can avoid by selling shares.