本研究主要探討摩根大通集團在2004年與Bank One的併購事件，採取 事件研究法檢定其併購事件是否對該集團股價造成影響；以併購宣告日(2004 年1月14日)作為事件日，宣告日前後各30日作為事件期，事件日前180天 至31天為估計期，統計檢定結果顯示本次購併對摩根大通集團並無顯著的 宣告效果。 在個案分析中，本文討論主併與被併雙方公司集團的背景，公司合併史 及2004年的併購時程表；分析併購策略及併購對此二集團之影響，並探討 因合併所產生的衝突及隱憂。結果發現Bank One的股價幅度在併購宣告日 後有明顯的上升，雖然摩根大通集團當日的股價並未出現預期中的高點，然 而整個2004年至今，摩根大通集團股價有穩定的上揚趨勢。在個案分析中 同時也就摩根大通集團之會計報表作一簡單的剖析，以比較其併購前後營業 淨利及資產的變動比，發現不論是在總資產報酬率或是股東權益報酬率都有 幾近倍數的成長。 This report summarized the studies on the effect of stock prices of J.P. Morgan in its merger with Bank One corp. in year 2004. Event Studies has been applied to analyze the stock price variations before and after the announcement of the merger. Using the merger announcement date January 14, 2004 as the event date and the event period being the 30-days before and after the announcement, there is no statistical significance that the announcement of merger has affected the stock price of JP Morgan in the said event period. In addition to historical stock prices, the analysis also covers the backgrounds of both companies involved in the merger, the merger histories of the companies, and the time table of the year 2004 merger. The strategies adopted in the merger and the effects of the merger on these two companies are also studied. This report also explored the conflicts and potential risk associated with the merger. The result of the studies reveals that there were significant rise in the stock price of Bank One after the announcement. For J.P Morgan, the stock price on the event date has not reached it estimated level suggested by the model. However, from year 2004 till now, there is a steady rising trend on the stock price of JP Morgan.