本文在垂直相關市場下,研究內生的廠商價格或數量選擇。假設在垂直相關市場中存在一家垂直整合廠商與一家獨立下游廠商,兩家廠商就中間財契約進行二部定價的談判。相異於文獻上的研究發現,本文證明Bertrand競爭與Cournot競爭都有可能是此賽局的均衡結果。其中,Bertrand均衡極大化產業利潤,然而卻存在策略變數類型選擇上的市場失靈。Cournot均衡極大化社會福利和消費者剩餘,然而卻存在策略變數類型選擇上的囚犯困境。我們最後證明,本文的市場架構,是允許廠商垂直整合的垂直相關市場下之均衡結果。

This research investigates the endogenous choice of prices versus quantities in a vertically-related market where an integrated firm competes with a downstream firm and they bargain over a two-part tariff input pricing contract. Contrary to the standard result, we show that both Bertrand competition and Cournot competition can be sustained as equilibrium outcomes. First, the Bertrand equilibrium maximizes industry profit, but there is a market failure in the choice of the type of strategic variables. Second, the Cournot equilibrium maximizes social welfare and consumer surplus, but there is a prisoners’ dilemma. This paper ends with an extension, showing that our baseline model arises naturally as the equilibrium outcome of a simple game that admits vertical mergers.