本研究探討蘋果公司iPhone的新產品宣告是否會對供應商股價有顯著影響，透過事件研究法對2013年至2017年間，iPhone5s/5c、iPhone6/6 Plus、iPhone6s/6s Plus、iPhone7/7 Plus，iPhone8/8 Plus/X的全球發表日進行異常報酬檢驗。過往文獻研究此類新產品宣告效果，大部分以固定合作的供應商為樣本進行檢驗，但每一年蘋果公司所公開的供應商有所增減，故本研究分別以近五年蘋果公司所公開的iPhone供應商為樣本進行研究。實證結果發現除iPhone5s/5c及iPhone6/6 Plus以外，其它年度的iPhone新產品宣告對供應商的股價多有顯著反應，呈現正向異常報酬，而在全球發表日後則產生負向異常報酬，顯示宣告效果有提前反應的現象，且在宣告日後有負向修正的現象。
This study investigated whether iPhone product launch announcements made by Apple Inc. (here after referred to as “Apple”) have a significant effect on the stock prices of its suppliers in the supply chain. An event study method was adopted to examine whether abnormal returns were observed in the stock prices of suppliers during global product launch announcements for iPhone5s/5c, iPhone6/6 Plus, iPhone6s/6s Plus, iPhone7/7 Plus, and iPhone8/8 Plus/X between 2013 and 2017.Most studies that have explored the effect of product launch announcements on suppliers’ stock prices have selected supplier samples comprising firms’ regular suppliers. However, the suppliers that are publicly disclosed by Apple change every year. Accordingly, this study selected publicly-disclosed iPhone suppliers over the past 5 years as its supplier sample. The empirical results revealed that except for the product launch announcement for iPhone5s/5c, iPhone6/6 Plus, all other product launch announcements for iPhones exhibited significant and positive effects on suppliers’ stock prices. Positive and negative abnormal returns were observed before and after global product launch announcement dates, respectively, indicating the effects of product launch announcement son suppliers’ stock prices; that is, their stock prices exhibited reactions prior to actual product release and revised after the product launch announcement dates.
