• 作者： 萬鍾汶; 黃文星
• 作者服務機構： 國立中興大學農業經濟學系
• 中文摘要： 日本香蕉市場長久以來皆為臺灣、菲律賓及厄瓜多爾三國香蕉高度集中的寡占市場結構，且臺蕉品質公認優於菲蕉及厄蕉，故日本香蕉市場特質近似經濟理論中的異質寡占(differentiated oligopoly)競爭。而臺蕉的出口早自1974年起便由臺灣青果運銷合作社（簡稱青果社）統籌負責出口集運作業，青果社相當於香蕉外銷的專賣機構。本研究旨在不完全競爭的市場結構下，以實證檢定臺蕉在日本市場中的異質性，並衡量青果社是否兼具寡買及寡賣力量，由之剖析臺蕉在日本市場的競爭能力。研究首先依廠商理論建立一個異質寡占最適化決策猜測變量模型，進而將之應用於青果社對內購入香蕉原料及出口香蕉的決策行為，透過對香蕉出口對手國的猜測彈性(conjectural elasticity)係數可衡量出日本香蕉市場異質寡占的程度。實證結果顯示臺蕉與其他國香蕉間確實存在不完全替代性，亦即存在產品差異性(product differentiation)。此外，青果社在日本香蕉市場非為價格接受者，並擁有輕度的市場力量。
• 英文摘要： The structure of Japanese banana market should be placed into the differentiated oligopoly categorybased on the two facts of that it is highly concentrated by the exports of three countries and productdifferentiation exists among exported bananas. On the other hand, the Taiwan Provincial Fruit MarketingCooperative has being the sole authorized banana exporting agency since 1974. Thus, this study intended toempirically analyze the competitiveness of Taiwan bananas in the Japanese market in terms of the oligopolyand oligopsony power exercised by the exporting agency under an imperfect competition framework. Ageneral conceptual model of optimization of differentiated oligopoly decision making behavior, in which thedegree of market imperfection was captured by the conjectural elasticity among exporting rivals, wasdeveloped initially. Then the conceptual model was empirically implemented into estimating the behavior ofthe Taiwan bananas exporting agency. Results showed that the Japanese banana market is not perfectlycompetitive. And as expected, Taiwan banana is differentiated with other bananas and its exporting agent isnot a price taker but possessing some oligopoly power.
• 中文關鍵字： 香蕉外銷; 異質寡占; 產品差異性; 精測彈性
• 英文關鍵字： Banana exports; differentiated oligopoly; product differentiation; conjectural elasticity