Vertical Merger Facilitation in Cournot Oligopolies with Complementary Inputs

本文利用互補要素模型分析科諾寡占市場之垂直整併誘因，並討論模型中存在的各種均衡市場結構。當上游的中間財一由獨占廠商生產，另一由寡占廠商生產時，獨占的中間財生產者的利潤會隨著垂直整併廠商家數增加而增加。其原因在於垂直整併廠商消除了雙重加價而降低生產成本，從而增加均衡產量並衍生對獨占的中間財之需求。由於獨占中間財廠商可以從其他廠商的垂直整併獲利，它甚至有誘因貼補其他廠商以促成垂直整併，使得產業均衡結構變成完全整併。本文亦支持垂直整併會促進效率的論點，並當有獨占勞工工會存在時，廠商進行產業垂直整併後會使得勞工工資上漲。因此本文結果可對反托拉斯法的垂直整併管制提供多元政策意涵，並對多要素投入的垂直相關市場有更全面的市場結構預測。The equilibrium industry structure is investigated in this research by using a complementary input model highlighting the vertical integration incentives in a Cournot successive oligopolistic market. The upstream input markets composed of a monopolist and N oligopolists would exhibit the increasing monopolistic rent as more vertically-integrated firms emerge in the market. This equilibrium is sustained by the production boosting outcome resulting from the circumvention of the double marginalization problem for the vertically-integrated producers which in turn drives up the derived demand toward the solely supplied upstream input. The more vertically-integrated firms in a market, the more profits a monopolist gains. There is an incentive for it to subsidise vertical integration. The result here also supports the efficiency-improving and the wage-increasing result stemming from the larger output and lower price in the final goods market after the vertical integration. This paper would shed some light on the antitrust regulation over the vertical integration in vertically-related markets composed of multiple complementary inputs