品質差異的雙占廠商之市場優勢分析

The Market Dominance in a Vertically Differentiated Duopoly

張瑞雲(Ray-Yun Chang)

垂直產品差異性 ； 高品質優勢 ； 品質決策 ； Vertical product differentiation ； high-quality advantage ； quality choice

興國學報

14期（2013 / 01 / 01）

151 - 162

繁體中文

在各類產品市場上，如汽車產業或食品產業，我們可以發現一個共同的特徵，那就是生產高品質產品的廠商不一定擁有較高的市場份額及利潤。然而，在垂直產品差異性的相關文獻中，大部分的研究結果卻都得到了「高品質廠商具有高市場份額及高利潤」的結論。為了探討此一現實與理論的不一致性，本文建立一個結合垂直產品差異性及基本效用的一般化模型，並藉此在數量競爭下探討廠商的品質選擇及市場的均衡結果。本文的研究結果發現，由於基本效用的存在，低品質廠商可能具有「高市場份額及高利潤的市場優勢」，此結果與大部分垂直產品差異性文獻的結論不同。再者，我們也發現隨著基本效用越大時，兩家廠商的均衡品質將會越小。

In many markets, like automobile and food industries, a common feature is that, the high-quality firms usually do not have neither a larger market share nor a higher profit. In most models of vertical product differentiation, however, it is well known that the high-quality firm always dominates both in terms of profit and market share theoretically. Accordingly, this paper proposes a general model combining baseline benefit settings to discuss whether the high-quality firm dominates in terms of profit and/or market share in detail under Cournot competition. We found that the low-quality firm acquires dominance in market share and profit when the baseline benefit is high enough. Besides, an increase in baseline benefit lowers Firm's quality.

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