2020年下半年美國金融市場逐漸從COVID-19帶來的負面影響中復甦，不只首次公開募股(IPO)數量激增，以特殊目的收購公司(SPAC)方式上市的數量也達到歷史新高。本研究旨在探討SPAC在收購完成宣告日對股價產生的影響，採用事件研究法分析2016年到2020年以SPAC方式IPO並完成收購的案例，第一部分設定15種事件窗口觀察異常報酬在各時間區段表現，第二部分建立實證模型討論SPAC中變數的影響及意義，第三部份透過將樣本分群比較高、低累積異常報酬股票群之間的差異。

研究結果如下：
(一) 收購完成宣告日對SPAC股價表現的影響並不顯著；然而以符號檢定法分析會發現事件期下跌的股票顯著多於上漲的股票。
(二) SPAC募集資金量與累積異常報酬呈正相關；目標公司市值與累積異常報酬呈負相關。
(三) 信息技術業在SPAC收購案中比其他產業更具優勢。
(四) 將樣本以累積異常報酬分群研究發現高報酬群的目標公司市值平均較高。

The U.S. financial markets gradually recovered from the negative impact of COVID-19 in the second half of 2020, with not only a surge in the number of initial public offerings (IPO), but also a record number of special purpose acquisition companies (SPAC). The purpose of this thesis is to explore the impact of SPAC acquisition completion announcement on stock price. Using a sample of completed SPAC from 2016 to 2020, and the event study method was used to analyze the abnormal return. This thesis is divided into three main parts. The first part sets 15 event windows to observe the performance of cumulative abnormal returns (CAR) in each window. The second part develops an empirical model to discuss the effect and significance of variables in the SPAC case. The third part compares the differences between stock groups with high and low CAR by dividing the sample into groups.

The findings suggest that:
1. The effect of the acquisition completion announcement on SPAC's stock price performance is not significant, however, the analysis by sign test method reveals that the number of declining stocks during the event period was significantly greater than the number of advancing stocks.
2. There is a positive correlation between the offering amount of SPAC's IPO and CAR; and there is a negative correlation between the market capitalization of target company and CAR.
3. Information technology industry has advantage over other industries in SPAC.
4. High CAR stock groups have higher market capitalization on average compare with low CAR stock groups.

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