本研究旨在探討母公司旗下子公司IPO對其普通股報酬之影響，觀察臺灣企業集團在成長過程中，可能會產生核心事業轉移或產生數個企業並重的情況，甚而至於將旗下獲利良好之子公司遞件申請上市，「母以子貴」概念股亦是投資大眾高度關注之題材。本研究利用事件研究法之市場模式評估民國95年1月1日之後子公司上市對母公司股票報酬率的影響，並加入林昌鴻(2005)之實證結果，實證結果顯示，不論是民國82年至94年(共129家樣本公司)、95年至107年(共91家樣本公司)或全體樣本(220家樣本公司)皆顯示，在子公司上市日當天對母公司的股價並無正面助益。實證結果亦顯示，在子公司上市日前10日若持有母公司股票至子公司上市日前1日可享有正的累積異常報酬，惟其在統計上不顯著，然而在子公司上市後，母公司股價必定下跌且統計上顯著。因此，我們推論市場上「母以子貴」概念股的現象在子公司IPO初期推升母公司股價之效果並不顯著。

This article discusses how subsidiary companies’ IPO impact the stock return of parent companies. The corporations of Taiwan tend to open up subsidiary companies for transferring core business, or expanding business line. Moreover they prefer to apply IPO for profitable subsidiary companies, thus investors in Taiwan always pay high attention to these “subsidiary stocks”. The article evaluate the impact of subsidiary companies’ IPO on their parent companies, through event study analysis, based on Lin’s(2005) results, and extend the sample period from 2005 to 2018. The analysis is performed on three data sets: 1) 1993-2005 (contained 129 samples); 2) 2006-2018 (contained 91 samples), and 3) 1993 – 2018 (contained 220 samples), and the empirical research shows within these three tests, the subsidiary company’s IPO have no positive impact on parent company’s stock return. The article also finds that there is a positive abnormal cumulative return on parent company’s stock during 10 days before IPO to d day before IPO, but there is no statistically significant result to prove it. Although, there is a statistically significant proof that parent company’s stock return would decrease after subsidiary company’s IPO. Therefore, based on the empirical result, this article concludes that the subsidiary company’s IPO has no significant positive impact on parent company’s stock return.

一、 緒論 ………………………………………………………………………………………………1
1-1 研究背景與動機 ……………………………………………………………………1
1-2 研究目的 …………………………………………………………………………………2
1-3 研究流程及架構………………………………………………………………………3
二、 文獻回顧………………………………………………………………………………………5
2-1 新上市公司股票(IPOs)的相關文獻………………………………5
2-2 母公司與子公司之間關係的相關文獻…………………………10
三、 研究方法……………………………………………………………………………………15
3-1 樣本選取與研究期間……………………………………………………………15
3-2 事件研究法與股票異常報酬……………………………………………15
四、 實證研究結果……………………………………………………………………………20
4-1 研究設計……………………………………………………………………………………20
4-2 實證結果…………………………………………………………………………………21
五、 結論與建議………………………………………………………………………………26
5-1 研究結論……………………………………………………………………………………26
5-2 研究限制……………………………………………………………………………………26
5-3 研究建議……………………………………………………………………………………27
參考文獻…………………………………………………………………………………………………28
附錄……………………………………………………………………………………………………………32

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11. 趙琪(2001)，「資源依賴與交易成本對海外子公司控制機制之影響－台灣企業與大陸子公司之實證研究」。中山管理評論，9(1)，87-109。
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