本研究旨在探討臺灣中型100 指數成分股調整事件之價量關係以及新聞報導效果。研究樣本分為純粹納入股、向下納入股、純粹剔除股以及向上剔除股，並分別以成份股調整之宣告日與執行日作為事件日，採用事件研究法，分析事件前後之價量變化，同時，進一步探討，宣告日至執行日期間，新聞報導對於成分股調整效果之影響。實證結果顯示，純粹納入(剔除)股於宣告日當天以及執行日前一天具有顯著的正(負)向異常報酬，且短期內皆有反轉的現象產生；向下納入(向上剔除)股，在宣告日與執行日前一交易日享有負(正)向異常報酬，且執行日後五日旋即反轉；此外，此四類個股於宣告日以及執行日附近，皆有異常週轉率生。在新聞效果部分，本研究將純粹納入(剔除)股分為有利多(空)新聞之組別以及無新聞之組別，探討其異常報酬現象。實證結果發現，有利多(空)新聞之純粹納入(剔除)股，相較於無新聞之純粹納入(剔除)股享有較高的正(負)向異常報酬率，顯見在成分股調整事件中，新聞報導亦會影響股價表現。 / This paper examines the effects of Taiwan mid-cap 100 index revision and news coverage on stock price and volume. Using event study method, the sample of this study is divided into four groups: pure additions, downward additions, pure deletions, upward deletions to analyze the changes of stock prices and volume on the announcement day and effective day. Furthermore, the effects of news coverage between announcement day and effective day are also investigated. Results of our analysis suggests that there are significantly positive (negative) abnormal returns (ARs) for pure additions (deletions) on announcement day and the day before effective day but transitory. For downward additions and upward deletions, there are significantly negative ARs for the former and significantly positive ARs for the latter. However, both ARs reverse within five days. Besides, there are abnormal volumes in the entire sample. As for the effects of news coverage, pure additions (deletions) are divided into two groups to examine the existence of ARs, one group with bullish (bearish) news and one group without. Results show that pure additions (deletions) with bullish (bearish) news have higher ARs than those without news coverage, supporting our hypothesis that in the event of index revision, news coverage do affect stock prices