本研究以民國91年至民國101年台灣進行公司分割之上市櫃公司為研究對象，探討市場對於企業宣告從事上下游分割之反應，以及公司治理對此反應之影響。研究結果顯示： 一、台灣公司宣告分割期間，異常報酬並不明顯。 二、分割後母子公司在產業鏈中具上下游關係者，其累積異常報酬較不具上下游關係者差。 三、內部人持股比例高、財務槓桿高，對分割之宣告效果有負面影響。 可見台灣許多企業雖期望透過公司分割落實代工與品牌分家，然而市場對於這些分割活動未必能給予正面評價。同時，內部人對對公司控制力大或者公司財務槓桿高，在宣告分割時小股東以及債權人可能擔心此分割活動將損及其利益。 / This study examines the effect of companies declaring their spin-offs and the impact of corporate governance variables on the effect with Taiwan listed spin-off companies during year 2002 to 2012 as samples. The empirical results can be summarized as below: 1. There is no significant abnormal returns (AR) while Taiwan companies declaring their spin-offs. 2. Spin-offs that parent companies and its subsidiaries are suppliers and downstream customers have lower abnormal returns. 3. “High insider shareholding percentage” and “high financial leverage” have negative impact on the effect of spin-offs declaring. According, although many Taiwan companies intend to separate their brand and OEM/ODM business through spin-offs, it is not necessary to result in positive effects on their share prices. Meanwhile, minority shareholders and creditors might worry about the spin-off affairs damage their benefit if the insiders have large control power to the companies or the companies have high financial leverages.