本研究以事件研究法分析2010年至2015年間,iPhone 4至iPhone 6s/6s+共六代機款之三個重要新產品宣告日:蘋果全球開發者大會WWDC、新iPhone全球產品發表日、新iPhone台灣上市宣告日,對台灣iPhone上下游24家上市櫃公司股價的宣告效果。 實證結果發現, 股市對WWDC之事件具有正向的宣告效果,且有提前反應之現象。同時在接近事件日時SCAR開始略為下滑,似乎存在過度反應的現象。 而在新iPhone全球產品發表日前,亦存在顯著為正的SAR,而隨著接近發表日,正向異常報酬消失,並開始出現顯著為負的SAR,顯示產品發表後市場有過度反應之現象。 最後以台灣上市宣告日為事件日之實證結果顯示,發現事件期間SAR大多顯著為負,SCAR也自事件日前便一路走低,並大多顯著為負。顯示台灣上市宣告日存在負向的宣告效果,頗有類似利多出盡的性質。
Since Apple Inc. launched the first iPhone in 2007, every new model of the product has been provoking smartphone market growth and enriching mobile application. The most successful smartphone transforms its users’ lifestyle and keeps the NO.1 market share. Therefore, how the new iPhone announcement impacts the stock price of the value chain companies causes investors’ concern. The study will find out the announcement effects of 3 important iPhone-related announcement dates: WWDC (The Apple Worldwide Developers Conference), the worldwide new iPhone launching ceremony, and the Taiwan new iPhone launching ceremony. We use event study as the methodology, choose sample companies from the supply chain vendors and channel companies in Taiwan, and verify the abnormal returns and cumulative abnormal returns from 2010 to 2015(iPhone 4 to iPhone 6s). The empirical results show that: first, WWDC announcement effect does cause significant positive abnormal returns before the event date. Second, the worldwide-new-iPhone-launching-ceremony announcement effect makes significant positive abnormal returns happen; however, the positive abnormal returns immediately reverse to the negative abnormal returns. Third, the Taiwan-new-iPhone-launching-ceremony announcement effect is quite different and leads to significant negative abnormal returns.