本文以事件研究法，使用2016年至2023年間進行收購的SPAC公司資訊，分析當SPAC公司宣布完成收購時，是否能為投資人帶來異常報酬，並利用比以往研究更多筆SPAC數據進行橫斷面分析，研究SPAC公司的累積平均異常報酬與目標公司市值、財務槓桿、目標公司之Tobin's Q、發行前的普通股數量、即將發行的認股權證數量及是否在COVID-19發生時期之間的關係，更深入的探討SPAC的成本與其能帶來的報酬，以及稀釋效應與COVID-19對投資人的影響。
研究結果顯示，SPAC公司在收購完成宣告日前後，平均異常報酬率(AAR)及累積平均異常報酬率(CAAR)皆有顯著為負的表現，但收購完成宣告日後的期間越長，此現象也越不明顯，我們的研究結果支持SPAC公司在完成收購宣告時，將為投資人帶來負報酬。
另一方面，橫斷面分析的結果顯示，目標公司市值與Tobin's Q對SPAC的CAAR有顯著正向的關係，而財務槓桿則無影響。發行前的普通股數量也對於CAAR無顯著影響，但即將發行的認股權證數量在收購完成宣告前3日到後5日的期間，對於CAAR都有顯著的負向影響，證明稀釋效應的存在，將降低投資人所獲得的異常報酬。最後，橫斷面分析也顯示在完成收購前，在COVID-19發生時期對於CAAR有顯著正向的影響，在完成收購後，則對於CAAR有顯著負向的影響。
本研究建議未來能將美國證券交易委員會針對SPAC公布有關揭露資訊的新規納入考量，也能針對SPAC創辦人的特徵、聲譽與媒體報導等面向進行研究，將能更全面的對SPAC 的異常報酬進行分析。

This study uses the event study method to analyze abnormal returns for SPACs upon acquisition announcements, using data from 2016 to 2023. It also examines the relationship between cumulative average abnormal return (CAAR) and variables like target company market value, financial leverage, Tobin's Q, common shares before offering, the number of warrants to be issued, and the COVID-19 period.
The empirical results indicate that SPACs show significantly average abnormal return (AAR) and cumulative average abnormal return (CAAR) around the acquisition announcement date. Cross-sectional analysis indicates that target company market value and Tobin's Q significantly impact CAAR, while financial leverage doesn't have a significant effect. The number of warrants to be issued significantly negatively impacts CAAR, highlighting the dilution effect. During COVID-19, CAAR is significantly positive before and significantly negative after acquisition completion.
Future research should consider the SEC's new disclosure regulations for SPACs and explore factors such as SPAC founders' characteristics, reputation, and media coverage for a more comprehensive analysis of SPAC abnormal returns.

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