摘要 本文主要探討研發活動對公司權益資金成本之影響,以及研發活動相關之敘述性揭露可讀性的調節效果。此研究將找出研發活動、研發活動相關之敘述性揭露可讀性以及權益資金成本三者的關聯。本研究以 2010 年到 2018 年台灣半導體業上市(櫃) 117 家公司為樣本資料,經由實證結果發現,研發活動對公司權益資金成本有顯著的正向關聯,本文推測企業執行研發計畫將提高內外部資訊不對稱問題,投資人將面臨較高估計風險並提高風險貼水進而影響公司權益資金成本。而研發活動相關之敘述性揭露可讀性對公司權益資金成本則有顯著負向關係,顯示公司提高研發活動相關之敘述性揭露可讀性確實能降低權益資金成本。此外,本研究也表示,研發活動相關之敘述性揭露可讀性對研發活動與權益資金成本之關聯具有顯著調節效果,亦即研發活動相關之敘述性揭露可讀性能顯著減緩研發密度對權益資金成本的正向影響。因此,透過實證結果指出,在台灣半導體公司樣本之下,研發活動與研發活動相關之敘述性揭露可讀性各別對權益資金成本有顯著影響,且研發活動相關之敘述性 揭露可讀性顯著影響研發活動對權益資金成本之關聯。;ABSTRACT This essay investigates the relation between R&D activity and the cost of equity capital, and attempts to find the moderating effect of the readability of narrative disclosure from R&D disclosures. Additionally, this study examines the relations among R&D activity, narrative disclosure from R&D disclosures, and the cost of equity capital, and conjectures the possible reasons behind their relations. A sample of 117 listed firms from 2010 to 2018 in semiconductor industry was used and other variables were also controlled. This paper finds that firms with higher R&D activity will have higher the cost of equity capital. We conjecture that executing R&D plans will intensify the problem of information asymmetry. Thus, investor will rise their estimated risk and companies will face higher cost of equity capital. The readability of narrative disclosure from R&D disclosures negatively associates with the cost of equity capital, which means that the readability of narrative disclosure from R&D disclosures truly influences overall value of firm. Then, this paper discovers the moderate effect of the readability of narrative disclosure from R&D disclosures on the relation between R&D activity and the cost of equity capital is significant, thus meaning that the readability of R&D disclosures will significantly mitigate the positive relation between R&D activity and the cost of equity capital. Therefore, through empirical analysis from Taiwan semiconductor industry, this paper points out R&D activity and the readability of narrative disclosure from R&D respectively have significant influence on the cost of equity capital, while the readability of narrative disclosure from R&D significantly impact the relation between R&D activity and the cost of equity capital.