本研究旨在運用事件研究法探討金融營業稅宣告對股價之影響，研究標的為台灣全體上市櫃金融業公司與各金融產業類股股價報酬率，其中各金融產業類股包含金控、銀行、保險及證券類。本實證研究有以下重要發現：一、財政部宣告調降金融營業稅至2％之訊息公布時（第一事件日）, 對台灣上市櫃金融業公司與各金融產業類股之股價產生顯著正的平均異常報酬率及平均累積異常報酬率；二、立法院三讀通過營業稅法修正案之訊息公布時（第二事件日），全體樣本公司的平均異常報酬率皆為正值；三、財政部宣告金融營業稅調高恢復至5％訊息公布時（第三事件日），對台灣上市櫃金融產業公司之股價產生負的平均異常報酬率及顯著的平均累積異常報酬率，而各金融產業類股之平均異常報酬率亦全部為負值；四、立法院三讀通過金融營業稅法修正案之訊息公布時（第四事件日），全體樣本公司的平均異常報酬率為負值；五、金融營業稅稅率調高至5％正式施行時（第五事件日），全體樣本公司之股價呈現顯著之負的平均異常報酬率。上述實證結果顯示金融營業稅變動宣告對台灣上市櫃金融產業公司股價存在影響。本文之結果除可提供主管機關參考，健全金融產業之發展外，亦可以提供投資人資訊，以作為投資依據。 The study aimed to adopt the event study method to explore the influence of declaration of business tax on the stock price. The research target was listed and OTC financial industries as a whole in Taiwan and the stock return of stocks of financial industries, including holdings, banking, insurance and securities. The important findings of the empirical research were listed as follows: 1. when Ministry of Finance declared the reduction of business tax to 2% (the date of the first event), a significant positive average abnormal returns and average accumulated abnormal returns showed in the influence on listed and OTC financial industries in Taiwan and the stock price of financial industries; 2. when Ministry of Justice declared the approval of amendment of Business Tax Act through the three-reading procedure (the date of the second event), the average abnormal return of entire sampling companies was positive; 3. when Ministry of Finance declared the increase of business tax to 5% (the date of the third event), the negative average abnormal returns and the significant average accumulated abnormal returns showed in the influence on the stock price of listed and OTC financial industries in Taiwan, and the average abnormal returns of stocks of financial industries were all negative; 4. when Ministry of Justice declared the approval of amendment of Business Tax Act through the three-reading procedure (the date of the fourth event), the average abnormal returns of entire sampling companies was negative; and 5. when the increase of business tax to 5% was implemented formally (the date of the fifth event), the significantly negative average abnormal returns showed on the stock price of the entire sampling companies. The empirical result mentioned above showed that the declaration of changes on business tax influenced the stock price of listed and OTC financial industries in Taiwan. The result of the study may be referred to by the authorities, and may be provided to perfect the development of financial industries. In addition, it can provide information about investment for investors for reference.
