本文以事件研究法探討國內生技化學產業新產品宣告對公司股價之影響，並檢視同業競爭策略型態、宣告公司之研發支出、負債比率和公司規模對宣告效果的影響。由實證結果發現：（1）新產品宣告在當日與次日會產生顯著為正的異常報酬率。（2）但該效果會因生技化學業各子產業別的不同而有差異，且新產品宣告後5～8日會產生顯著為負的異常報酬率；亦即生技化學產業公司新產品宣告股價可能會因過度反應，而產生異常報酬率反轉現象。（3）考量同業競爭策略型態，新產品宣告在策略替代型環境下（較在策略互補型環境下），其新產品宣告更能產生正向效果。（4）研發支出、負債比率越高的公司，其宣告效果越顯著；公司規模則對宣告效果無顯著影響。

The effect of new product announcements is examined by the event study methodology to investigate on firms' values of biotechnology companies in Taiwan. The study also examines announcement effect from firms' characteristic variables of R&D spending, debt ratio, and company size. Especially, the study uses the competitive strategy measure (Sundaram et al., 1996) to measure competitors' interactions. The findings are as follows: (1) Significant and positive abnormal returns are found during the first two days of new product announcements. (2) The degree of new product announcements effect is different in tiers of biotechnology company. Besides, significant and negative abnormal returns are found during from fifth to eighth day after new product announcements.The reverse of abnormal return indicates the phenomenon of overreaction when new product is announced by biotechnology companies. (3) The market value introductions are announced by firms in strategic substitute competition more positive effects than those announced by firms in complements competition. (4) The announcing firms' stock prices are positively influenced by a change in research spending, or debt ratio, but the effect of company size is not significant.