本研究探討公司提列商譽減損時的市場反應以及經理人認列商譽減損的動機。實證結果發現，在未控制盈餘宣告效果下，提列商譽減損公司的股價在減損宣告前公司存在正向股價異常報酬，在宣告日後則存在顯著負向的異常報酬。但在控制盈餘宣告效果後，商譽減損的訊息並不會提前反應，宣告前之正向異常報酬源自盈餘宣告正向效果，表示經理人會選擇在盈餘有好消息時宣告商譽減損。至於宣告日後，資產減損金額對累積異常報酬具有顯著解釋能力，減損比率愈高，則累積異常報酬愈差。在認列商譽減損的決定因素部分，本研究支持商譽減損的提列是除了報導因素，也存在經濟因素。

In this paper we examine the market reaction to goodwill impairment loss and the determinants of recognition of goodwill impairments. Positive pre-event abnormal returns and negative post-event abnormal returns are observed around the write-offs announcement. After controlling for the potential earnings announcement effects, we find that the pre-event abnormal returns are not significantly related to impairment losses. This implies that observed positive stock reaction before the announcement date is attributable to the good earnings news and managers tent to announce goodwill write-offs when earnings news is good. The post-event abnormal returns are significantly negatively related to impairment losses after controlling for earnings announcement effects. The regression results support the arguments that goodwill impairment announcements have negative impacts on stock returns and the information of goodwill write-offs does not leak before the announcement date. As to the determinants of recognition of goodwill impairments, the empirical evidence shows that goodwill impairment losses are associated with the loss of economic values of goodwill and the managers’ discretionary behaviors.