本研究透過事件研究法，以德國BNT疫苗通過緊急使用授權是否會造成台灣上市上櫃跨國企業之股價異常報酬以及是否存在消息洩漏之現象。檢定結果指出，在事件日當天及事件日前第三日，皆呈現顯著的正向異常報酬。此外，在事件期間的其他交易日就再也沒有出現俱有相當顯著水準。類似的負向異常報酬也出現在事件日前的第一日及第五日與事件日後第四日均呈現負向顯著異常報酬。此研究結果顯示，因實際核准緊急授權的時間相對各界的期待已有相當的延後落差，市場的反應則不如預期，而新冠病毒不斷演變，也讓投資人存有疑慮，不敢冒進加碼。此外，在我們的研究結果中，無法證明通過緊急使用授權消息是否提前洩漏。

This study investigates whether the emergency use authorization of the German BNT vaccine would lead to abnormal returns in the stock prices of listed and over-the-counter multinational companies in Taiwan, as well as the existence of any leakage of information prior to this event. The results of the tests indicate significant positive abnormal returns on the event day and the third trading day before the event. Furthermore, no significant abnormal returns were observed during the other trading days of the event period. Similar negative abnormal returns were significantly found on the first and fifth days before the event and the fourth day after the event. These findings suggest that there was a considerable delay in the actual approval of the emergency authorization compared to the expectations of the market, and the market's response exhibited relatively mild. The continuous evolution of the COVID-19 virus also raised concerns among investors, leading them to refrain from increasing their positions. Additionally, our study results were unable to confirm whether there was any early information leakage of vaccine emergency use authorization.