本文主要研究兼收并购目标公司进行股权回购对于并购结果的影响。通过对美国1995年至2010年间媒体报道可能收到并购要约的公司样本进行分析，本文主要有以下发现：首先，股权回购能够降低目标公司实际收到并购要约的可能性；其次，对于市场传闻属实，的确收到要约的公司，股权回购能够降低公司被成功收购的概率。以上的发现与理论研究相符合，证明了股权回购能够有效的阻止目标公司被收购。进一步的，本文分析了该种防御性股票回购对于目标公司股东的影响。假设目标公司管理层进行回购的目的仅仅是为了自身利益而防止公司被收购，那么该举措将降低公司的价值以及股东的回报率。相反的，如果目标公司管理层进行回购的目的是防止公司价值被低估，并提高其在并购谈判中的议价能力，那么该举措将增加公司的价值以及股东的收益。通过对成功的并购案例进行实证分析，本文发现股票回购能够提高目标公司在并购整个过程中的收益。具体地，进行股权回购的目标公司相比收到现金的可能性增加，收到现金所占整个交易额的比例增加，并能获得更高的报酬率。另外，收购方的收益并不会随之增加，说明回购使得市场上调对于目标公司的估值，并且全部相应的收益都被目标公司得到。这从另一个方面说明目标公司的议价能力上升。 / This paper examines the effect of target share repurchase on outcomes of possible takeover attempts between 1995 and 2010. Consistent with deterrent effect hypothesis, I find that rumored targets are less likely to receive actual bids if they use share repurchase as a self-defense strategy. Moreover, for the subsample of rumored targets that receive bids afterwards, I find a significant negative relation between share repurchase and the likelihood of deal completion. Furthermore, I test the hypothesis that share repurchase is used by self-interested target managers for entrenchment purpose, and as a result the cost of signaling may lead to lower premiums for target shareholders. As an alternative hypothesis, share repurchase may increase bargaining power of target managers and result in better negotiated terms. Consistent with the enhanced bargaining power hypothesis, I find that target share repurchase is associated with higher probability of receiving cash as part of payment, with higher percentage of cash received, and with higher target takeover premiums. / Detailed summary in vernacular field only. / Xia, Yidan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 29-30). / Abstracts also in Chinese. / Chapter I. --- Introduction --- p.1 / Chapter II. --- Data collection and summary statistics --- p.6 / Chapter A. --- Sample Construction --- p.6 / Chapter A.1. --- Rumor sample --- p.7 / Chapter A.2. --- Complete Sample --- p.8 / Chapter B. --- Sample Description --- p.9 / Chapter C. --- Variable Construction and Summary Statistics --- p.11 / Chapter C.1. --- Repurchase variables --- p.11 / Chapter C.2. --- Premiums --- p.12 / Chapter III. --- Empirical Results --- p.17 / Chapter A. --- Deterrent Effect --- p.18 / Chapter A.1. --- Probability of Receiving Actual Bid --- p.18 / Chapter A.2. --- Probability of Deal Completion for Firms Received Bid after Rumor --- p.19 / Chapter B. --- Bargaining Power --- p.20 / Chapter B.1. --- The Relation between Repurchase and Payment method --- p.20 / Chapter B.2. --- The Relation between Repurchase and Target Premiums --- p.22 / Chapter B.2. --- The Acquirer Returns --- p.24 / Chapter IV. --- Conclusions --- p.27 / Appendix --- p.28 / References --- p.29 / Tables --- p.31