寡占廠商的目標選擇與數量競爭

本研究建立兩階段賽局模型，探討一般化寡占廠商的目標選擇與數量競爭。寡占廠商先在賽局第一階段同時決定其個別目標為追求「利潤極大化」或是追求「收益極大化」；在賽局第二階段，廠商依其目標同時決定其個別產量。在線性的需求與相同成本下，本研究得到以下結果：（1）市場規模的大小為賽局均衡之關鍵因素。如果市場規模夠大，則所有廠商都追求「收益極大化」；當市場規模較小時，則所有廠商都追求「利潤極大化」；如果市場規模適中，則部份廠商追求「利潤極大化」，而其餘廠商追求「收益極大化」，而且選擇追求「利潤極大化」廠商的產量與利潤，低於選擇追求「收益極大化」廠商的產量與利潤。（2）對於社會福利與消費者剩餘而言，所有廠商都選擇追求「收益極大化」時，社會福利與消費者剩餘最高，然而，對廠商而言，卻是一個囚犯兩難的均衡結果。

關鍵字

內生廠商目標；數量競爭；利潤極大化；收益極大化

並列摘要

This paper investigates objective choice and quantity competition in a generalized oligopoly model. The model herein is a two-stage game. In the first stage, oligopoly firms simultaneously and independently choose their respective objective (either profit maximization or revenue maximization). Then, in the second stage, they compete in quantity according to their objective. With linear demand functions and linear production cost functions, the results are as follows: First, the market size plays a crucial role in equilibrium outcome. When the market size is large (small) enough, all firms choose the same objective to maximize their respective revenue (profit). When the market size is moderate, some firms choose profit maximization, while the remaining firms choose revenue maximization. And the profit of the firms choosing profit maximization will be less than that of the firms choosing revenue maximization. Second, when all firms choose revenue maximization, social welfare and consumer surplus are both maximized, while it is a prisoner's dilemma outcome.