以往探討仿冒行為的文獻，大都只考慮單層市場中的仿冒問題，但實務上，上游中間財廠商所決定的中間財價格對下游最終財廠商的決策有著重要的影響。本文建立一垂直差異化模型，假設在一垂直相關市場中，上游市場存在一家獨占的中間財廠商，下游市場則存在一家正版廠商與多家可能進入的仿冒廠商，討論仿冒的出現對上游廠商以及下游正版廠商的影響。 本文發現，當考慮到存在中間財時，仿冒的出現可能會降低中間財的最適訂價，導致正版品的最適訂價與銷售量可能增加或減少，進而使正版廠商的利潤可能因仿冒的出現而增加。此一結果打破過去傳統文獻在不考慮網路外部性時，普遍認為仿冒的出現必定會使正版廠商的利潤減少的論點。此外，本文延伸探討當上游市場中的中間財廠商家數不只一家的情況，也發現到，仿冒的出現仍可能存在使正版廠商利潤增加的結果。此在在顯示中間財在探討仿冒議題上乃不可或缺的考慮因素。 Earlier studies often use a one-tiered market framework to discuss some issues about counterfeiting. However, in the real world, the pricing of the intermediate goods decided by upstream firm is important for the decision of the final goods firms. Thus, this paper establishes a model of vertical product differentiation to discuss the impacts caused by counterfeiting on the upstream firm and the downstream firm whose products are original or genuine. In the model, we assume there are an upstream firm and several downstream firms in a vertically related market. The upstream firm which is a monopolist specializes in producing intermediate goods and supplies them to the downstream firms, and the downstream firms include an original firm and many counterfeiters. The main finding in this paper is that, as counterfeiting may occur, the optimal price of intermediate goods may decrease and the optimal price and sales of original products may either increase or decrease. And then, the profit of the original firm may increase, this result is quite different from the previous counterfeiting literatures’ conclusion: without network externality, counterfeiting has a negative effect on the original firm’s profit. Moreover, if the quantity of the upstream firms is endogenized, it is still possible that the original firm’s profit increase as counterfeit occurs. This point proves that it is essential to take the intermediate goods into consideration when exploring counterfeiting issues.
