隨著科技日益進步，競爭越趨激烈，為早日進入市場，搶得
先機，獲取高額利潤，企業經常透過合作來達到外部成長、增加
競爭優勢等目的，策略聯盟及企業併購則是企業最常見之企業行
為，本研究透過Porter 之五力分析來將各樣本作分類，以產業競
爭觀點之角度為出發點，並用事件研究法來分析當企業宣布合作
時，對其股價有無異常報酬之影響。研究結果發現，策略聯盟樣
本之股價，在消息宣布後隔天即有正的顯著異常報酬，但隨後即
轉為負向報酬，股價反應消息迅速；而企業併購之樣本之股價在
事件日前後均未發現顯著之異常報酬，顯示資訊可能產生外溢。
此外透過橫斷面複迴歸分析也發現在策略聯盟部分，長期負債佔
資產比率皆為顯著正向影響；而企業併購部分除長期負債佔資產
比率外，代表成長機會的Tobin’s q 值同樣也呈現顯著正向影響。
Technological advances and increased competition recently, firms usually through
co-operation strategic to enter the market quickly, got the high profits, and to achive external
growth, increasing the competitive advantage. Now strategic alliances
and mergers and acquisitions behavior was the strategic what we always seen. In this
research, we used the five forces analysis (Porter, 1980) to separate and classify each
samples, try to use the view of industry competition, and use the event study methodology
to analyze whether the abnormal return happened when the enterprise announced
the news of co-operation relation. First the results show the significant abnormal return
when firms announced co-operation in the samples of strategic alliance, shares reflected
the news quickly, but we didn't see the same result in the samples of mergers and acquisitions,
it's means information spillover. Second, through the cross-sectional regression
analysis, we found the long-term liabilities to total assets ratio was significant in part
of the strategic alliance, and long-term liabilities to total assets ratio, and the Tobin's
q are significant in part of mergers and acquisitions.
