Google Trends關鍵字搜尋與台灣上市金控公司股價之探討

Abstract

2015~2016年間台灣金融業發生許多重大新聞事件，隨著資訊科技普及，網路搜尋已成為大眾獲取資訊的重要管道。本文利用Google Trends關鍵字搜尋指數作為網路關注度的代理變數，進行與台灣上市金控公司股價報酬相關之研究。\n 本文使用三種研究方法進行探討，首先利用圖表式比對法，初步觀察異常搜尋指數與異常報酬出現時間之關聯性，結果並未發現搜尋指數與台灣上市金控股價報酬間有明顯且一致的關係；接著套用向量自我迴歸模型進行分析，然而14家台灣上市金控公司中，僅從兆豐金數據可發現前一期搜尋指數的異常變動量增加1%將使下一期異常報酬率下降約2.67%；最後參考相關文獻使用Fama Macbeth兩階段迴歸模型，結果發現平均而言搜尋指數的異常變動量每上升一個標準差會顯著影響兩週後股價的異常報酬率下降約0.17%，SVI對於股價報酬影響為負向符合本文研究動機與背景，且有相關文獻指出投資人對於壞消息的反應較慢，因此使股價報酬有延後反應的現象，但無法解釋兩週的反應時間，因此對於這樣的研究結果持保留的態度。\n 總結三種研究方法所得結果，本文認為網路關注度對於目前台灣上市金控公司股價的影響仍然有限。

It’s unquiet for Taiwanese Financial industry between 2015 and 2016. There has been a lot of major news. With the popularity of information technology, Internet search has become an important channel for public access to information. Therefore, we use Search Volume Index (SVI) as a proxy for public online attention and conducts research related to the stock returns of listed financial holding companies in Taiwan. \n In this paper, three kinds of research methods are used. The first way is chart comparison method for preliminary data analysis. The results couldn’t show a clear and consistent relationship between SVI and stock returns. The second method is vector self-regression model. However, only Mega financial holding company’s result indicates abnormal search volume index(ASVI) increase 1% will decrease next week abnormal return by 2.67%. At last, we use Fama Macbeth two-stage regression model and find that on average 1 standard deviation increased in ASVI will decrease abnormal return by 0.17% after two weeks. The negative impact of SVI on the stock returns of financial holding companies is in line with the research motivation and background, and some relevant literatures prove that investors’ response to the bad news is slow, which leads to the delayed response of stock returns. However, the two weeks of reaction time for stock returns is unknown.\n In conclusion, this paper finds out that the impact of public online attention on share price of listed financial holding companies in Taiwan is still limited currently.