近年來由於科技的進步與自由化的趨勢下,使得公司投資活動不斷的複雜化,而企業為了永續經營必須不斷的成長,藉由規模的擴展、技術的提升、產品的創新及多角化等方式來提高市佔率及財務績效,因此投資活動是追求公司價值的方式之一,但由於投資活動對於投資結果的不確定性,因此是否公司會利用投資活動進行盈餘管理而操縱財務績效美化財務報表為本研究重點之一,另外多角化是公司投資活動之結果,因此多角化程度亦有可能造成對盈餘管理之影響。故本研究主要探討投資活動、多角化程度與盈餘管理之關係,其中投資活動部分主要探討公司的資本支出與異常資本支出。研究目的首先驗證投資活動與盈餘管理之關係。第二,探討多角化程度是否會減緩或者是惡化公司的盈餘管理活動。第三,討論投資活動與盈餘管理之間關係是否會因為多角化程度而有所影響。最後則是探討不同多角化程度及盈餘管理程度對於Berge and Ofek (1995)定義之公司超額價值影響。實證結果發現,首先,公司的資本支出水準與盈餘管理呈負相關,即資本支出水準低的公司其盈餘管理程度較大,但檢定結果並不顯著,但若以探討異常現象的異常資本支出則可以得到很顯著的發現,即公司的異常資本支出與盈餘管理活呈現顯著正相關,即不論是公司從事過度投資或者是低度投資活動皆存在高度的盈餘管理。第二,部門多角化可以減緩公司約6%的盈餘管理活動,主要原因為部門多角化會使得資金分散在不同的部門,造成不同部門之會計科目較不完全具相關性,因此傾向在部門間彼此沖銷,故使得管理者較難去從事盈餘管理,並且若同時結合部門及國際多角化亦可以減緩公司從事盈餘管理活動,另外實證結果發現國際多角化並沒有顯著的影響公司的盈餘管理活動。第三,高多角化程度有助於減緩投資活動所造成的盈餘管理。最後,盈餘管理程度與多角化程度皆與公司超額價值呈負相關,並且發現單部門公司在盈餘管理程度越高之下,其公司超額價值顯著越低,但這個現象在多部門公司中並不明顯。 This study discusses the relationship between corporate investments, diversification and earnings management. The corporate investments are defined capital investment and abnormal capital investments. First, we examine the relation between earnings management and corporate investments. Second, we determine whether earnings management is exacerbated or alleviated in diversified firms. An explicit distinction made between Multi-segment and Geographic diversification. Third, we investitage diversification change the relationship between corporate investments and earnings management. Finally, we examine the effect of diversification and earnings management to excess value using Berger and Ofek (1995).We find first, the results indicate that abnormal capital investments are positively associated with earnings management. Second, the evidence shows that earning management is mitigated 6% in Multi-segment diversified firms. The evidence also shows that a combination of Multi-segment diversification and global diversification helps alleviate earnings management. Imply that diversified firms derive their cash flows from disparate business divisions. The accruals generated by these business divisions are imperfectly correlated and tend to offset each other at the entire firm’s level, making it difficult for managers to manage earnings considerably in either direction. And global diversification alone, however, does not appear to impact earnings management. Third, high diversification can mitigate earnings management caused by abnormal capital investment. Finally, we find diversification and earnings management will decrease excess value.