雖然國內論文對企業併購的研究不在少數，範圍涵蓋併購的動機、類型、績效、策略與法律等，但針對敵意併購的研究則甚少，且研究大多著重於目標公司反接管策略的探討，鮮少對敵意併購後的績效進行討論。因此，本研究欲藉由資料包絡分析法，衡量我國敵意併購目標公司於併購發生後的經營效率變動的情況，及探討國內企業敵意併購之動機。 本研究以1986年至2001年台灣的併購活動為研究對象，實證發現主併者在選擇善意或敵意併購目標時有所差異；主併者選擇在善意併購目標公司時，對於目標公司之經營績效並無特別偏好；但在選擇敵意併購目標公司時，則以經營效率不佳者為對象，並透過敵意併購改善其經營效率；此外，敵意併購目標公司在替換掉管理能力不佳的管理者後，其效率進步的程度大於善意併購目標公司。因此，本研究樣本顯示台灣敵意併購支持懲戒式接管的動機假設。 / / Many scholars did researches on merger and acquisition (M&A) before, and the research scope involved motives, types, performance, strategies and laws of M&A; however, few of them mentioned hostile takeovers. Besides, most of hostile takeovers researches focus on anti-takeovers defenses of target companies, only a few researches discussed about post-takeover performance after hostile takeovers. This research attempts to measure the efficiency change of target companies after hostile takeovers, and discuss the motives of hostile takeovers in Taiwanese enterprises. The sample year includes Taiwan from 1986 to 2001. The research findings reveal that in the samples of friendly takeovers, there were no specific preference for choosing the targets companies. On the other hand, in the samples of hostile takeovers cases, the research findings denote that most of the target companies were underperformance, which triggers the takeover action. Moreover, the result demonstrates that hostile takeovers present better performance improvement than friendly takeovers do. The findings support hostile takeovers disciplinary motives implication in Taiwan.

Companies spend trillions of dollars on mergers and acquisitions (M&A) every year, and tens of thousands of new M&A deals are announced every year. However, despite the huge costs, only 10% to 30% of the M&As announced, get finalized (Christensen et al., 2011).There is extensive research conducted on why M&As fail, and their implications for the companies involved in the transaction. However, these large deals do not only impact the firms directly involved in the deal.  Microsoft, one of the world’s most influential companies, made on the 18th of January 2022 an acquisition announcement regarding its intent to acquire Activation Blizzard, one of the world’s largest game studios. The announcement made headlines all over the world and resulted in protests from competitors of the two companies. One of these competitors, Sony, experienced a 13% drop in stock price due to the acquisition announcement.  This thesis investigates the effect of acquisition announcements on the stock return of competitors to the target company. The study is examining the competitors stock return during the month leading up to the announcement, as well as the stock return during the month following the announcement. The authors have taken inspiration from a previous study “Acquisitions: A curse or blessing for direct competitors? The impact of target ownership structure” conducted by Mataigne et al. (2021).  By reviewing over 700 market reactions to acquisition announcements over a 10-year period, the authors were able to statistically test the differences in mean stock return. The authors were able to conclude that acquisition announcements have a negative impact on the stock return of competitors, and thereby answer the proposed research question: “What is the effect of acquisitions announcements on the stock returns of target company’s competitors in Sweden?”. Competitors to the target firm of an acquisition will experience the most significant change in their stock returns in the time period close to the announcement, after which the reaction will stabilize. The empirical findings of the study contribute to the field of knowledge using Behavioral Finance, the Efficient Market Hypothesis, the Capital Asset Pricing Model, the Stakeholder Theory, the Mitchell Model, and various market valuation methods.  Evidently, theories as part of the Behavioral Finance scope, such as the Efficient Market Hypothesis, provide support to the findings following the acquisition announcement. Theories such as the Stakeholder Theory and the Mitchell Model have helped identify competitors' stakeholder role to show how various events and organizations affect them as stakeholders in the market.  This study, which utilizes over 60.000 datapoints from daily price data for its analysis, takes a deductive approach within the positivist paradigm framework. The data is statistically tested using paired t-tests.

Ce travail vise à déterminer dans le cadre des sociétés s’introduisant en bourse les facteurs explicatifs de la présence d’engagements contractuels par les principaux actionnaires d’une part et leur impact sur la valeur de la firme d’autre part. Le terme « engagement contractuel » fait référence à deux mécanismes mis en place au moment de l’introduction en bourse : les engagements de conservation d’actions par les dirigeants et les pactes d’actionnaires. Notre étude porte sur un échantillon de 292 entreprises introduites en bourse entre 1996 et 2000 sur le nouveau marché et le second marché de la bourse de Paris. Nos résultats montrent que la présence et la durée des engagements de conservation d’actions des dirigeants servent à signaler la valeur de la firme lorsque l’asymétrie d’information est grande mais aussi à compenser certaines inefficiences du système de gouvernance de l’entreprise. Nous observons également un impact négatif sur la valeur de la firme des engagements de conservation des dirigeants alors que ceux concernant les sociétés de capital risque l’influence positivement. Concernant les pactes d’actionnaires, nos travaux montrent que leur mise en place est d’autant plus probable que les dirigeants anticipent une cession future de l’entreprise. Ils ont par ailleurs une influence positive sur la valeur de la firme tant qu’ils ne protègent pas les signataires d’une prise de contrôle hostile ; dans ce dernier cas l’effet sur la valeur de la firme est négatif. Finalement, nous montrons qu’il existe une réaction négative du cours de bourse autour du jour de l’expiration des engagements de conservation. / Using a sample of IPO firms, we try to figure out what are the factors influencing the adoption of lockups and shareholder agreements and we also try to assess the impact on firm value of these two commitments. Our study is based on a sample of 292 IPOs made between 1996 and 2000 on the French nouveau marché and second marché. We found that the adoption of lockups and their length may serve to alleviate information asymmetry at the IPO time. Our results also give pieces of evidence that this mechanism may compensate for some inefficiencies of the corporate governance setting. We found that lockups undertaken by managers have a negative effect on firm value whereas lockups by venture capital firms have a positive one. With regards to shareholder agreements, our tests show that the probability of adopting such a commitment is positively related to managers’ anticipation of a future sale of the firm. We also found that shareholder agreements have a positive effect on firm value as long as they do not insulate the company from the threat of a hostile takeover. In this latter case, the effect on firm value is negative. Finally, we found a negative return around the day where lockups are released.