Mixed oligopolies are characterized by private and public enterprises. Previously, entry into these markets was restrictive. It has since been relaxed by deregulations, and as a result, private firms have entered mixed oligopolies. An increase in the number of private firms increases competition among them and reduces the profit of incumbent private firms, given the privatization policy remains unchanged. However, an increase in the number of private firms may affect privatization policy, and thus, indirectly affect private firms' profits. Therefore, the overall effect on private firms' profit is ambiguous. In this study, we investigate how the number of private firms affects the profit of each private firm in mixed oligopolies. We use a linear-quadratic production cost function, which covers two popular model formulations in the mixed oligopoly literature. We show that if the degree of privatization is exogenous, the profit of each private firm decreases with the number of private firms. However, if the degree of privatization is endogenous, the relationship between the number of private firms and profit takes an inverted-U shape under a plausible range of cost parameters. Our results imply that there can exist multiple equilibria in free-entry markets with different degrees of privatization.

中文翻译：

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混合寡头中的利润增加条目

混合寡头垄断的特点是私营和公共企业。以前，进入这些市场是有限制的。此后，由于放松管制而有所放松，因此，私营公司进入了混合寡头垄断。鉴于私有化政策保持不变，私营企业数量的增加会加剧它们之间的竞争并降低现有私营企业的利润。然而，私营企业数量的增加可能会影响私有化政策，从而间接影响私营企业的利润。因此，对私营企业利润的总体影响是模糊的。在这项研究中，我们调查了私营企业的数量如何影响混合寡头垄断中每个私营企业的利润。我们使用线性二次生产成本函数，它涵盖了混合寡头文献中的两种流行模型公式。我们表明，如果私有化程度是外生的，每个私营企业的利润随着私营企业数量的增加而减少。然而，如果私有化程度是内生的，那么在合理的成本参数范围内，私营企业的数量与利润之间的关系呈倒 U 形。我们的结果意味着在不同私有化程度的自由进入市场中可能存在多个均衡。在合理的成本参数范围内，私营企业的数量与利润之间的关系呈倒 U 形。我们的结果意味着在不同私有化程度的自由进入市场中可能存在多个均衡。在合理的成本参数范围内，私营企业的数量与利润之间的关系呈倒 U 形。我们的结果意味着在不同私有化程度的自由进入市场中可能存在多个均衡。