近年減資題材日益漸增，在減資話題熱絡的同時，相對多數投資人認為只要公司實施減資策略將是適合的投資，減資再細分為虧損減資及現金減資，在過去2011年至2017年，由虧損減資居多到目前已經以現金減資為居多，媒體也紛紛報導某家公司實施減資股價飆漲等新聞資訊，使得投資人認為減資就是可以搶快進場的股票。
本研究將以效率資本市場假說推論以及事件研究法之GARCH風險調整模式進行股價是否有異常報酬表現探討，對於從2011年初至2017年底之上市公司實施減資對股價影響研究，探討在宣告減資前與減資後，股價相對變化。
再進一步分析將其進行減資之公司產業分類，減資二次以上之減資公司類別股、被動元件產業族群及電子零組件產業類別減資後股價是否有正異常報酬，藉此分析各類別的公司在減資前後的股價變動。
最後透過先公告減資後現金增資之公司進行減資前後股價是否有異常報酬。
In recent years, the theme of capital reduction has been increasing. At the same time as the topic of capital reduction, the majority of investors believe that as long as the company implements the capital reduction strategy, it will be a suitable investment. The capital reduction will be further divided into loss reduction and cash reduction. In the past 2011 to 2017, most of the losses and capital reductions have been mostly reduced by cash. The media also reported that a company has implemented news information such as soaring stock prices, which makes investors think that capital reduction is a stock that can quickly enter the market.
This study will use the efficiency market hypothesis inference and the GARCH risk adjustment model of the event study to discuss whether the stock price has abnor-mal returns. For the listed companies from the beginning of 2011 to the end of 2017, the company will implement capital reduction on the stock price. The impact study explores the relative change in stock prices before and after the reduction of capital.
Further analysis of the companys industrial classification that reduces capital, and whether the stock price of the reduced-capital company, the passive component industry group, and the electronic component industry category after the capital reduction is more than abnormal, so that the companies in each category are reduced. Stock price changes before and after.
Finally, through the company that announced the capital increase after the capital reduction, whether the stock price has abnormal returns before and after the capital re-duction.
