| 摘要: | 本論文利用混合寡占模型來分析政府的最適民營化政策。我們探討三個重要且仍被民營化文獻忽略的議題，分別為：廠商生產過程會污染環境、產品具有網路外部性的特質以及廠商進行價格競爭三種情況下的最適民營化政策。
在第二章中，我們探討廠商生產過程會對環境產生污染的情形下，政府的最適民營化政策。本章發現，存在環境污染下，公營廠商的產量不一定比民營廠商多，且民營化不一定會使公營廠商減產。當生產的邊際環境損害夠大時，本章得到與傳統民營化文獻不同的結果，即民營化程度提高會使公營廠商增產，民營廠商減產。其次，民營化不一定能改善環境。當生產的邊際環境損害夠大（小），則民營化後會使環境惡化（改善）。此外，只要環境損害函數為線性函數，則最適民營化程度完全不受污染的邊際損害程度大小所影響；然而，若環境損害函數為遞增（遞減） 函數，最適民營化程度會隨著單位污染程度增加而提高（降低）。
第三章則分析當產品具有網路外部性且產品間可能為相容或不相容的情況下，公營廠商的最適民營化程度。我們發現，網路外部性程度提高時，公營廠商會增產，但民營廠商則不一定會因而增產。其次，最適民營化程度並不一定會隨著網路外部性的增加而降低。一般而言，網路外部性的存在會使政府為了維持較多的產量而降低最適民營化程度，但在產品不相容且邊際成本遞增速度很快時，最適民營化程度反而會隨著網路外部性的增加而提高，使得存在網路外部性下的最適民營化程度反而比不存在網路外部性下來得高。最後，產品不相容下的最適民營化程度並不一定比產品相容下來得高，其決定於邊際成本遞增的速度。
第四章探討公營與民營廠商進行價格競爭下，兩廠商的最適訂價策略與政府的最適民營化政策。我們發現，公營廠商的均衡價格不一定會低於民營廠商，甚至有可能會高於民營廠商的價格；其次，民營化不一定會使公營廠商提高價格。若公營廠商的成本很高，則民營化反而會使公營廠商降低價格；最後，就一般的認知，越無效率的公營廠商越應該民營化，然而，我們發現，若公營廠商越沒有效率，則越不應該民營化。
最後，第五章總結本論文並提供未來研究方向。
;This dissertation applies a mixed oligopoly model demonstrating the optimal privatization policy on three issues: environmental damage, network externalities, and price competition.
Chapter 2 explores the effect of privatization on firms’ equilibrium output given that environmental pollution will emerge during the production process. The interaction between the privatization policy and the environmental damage is also analyzed. We find that if the production process accompanies pollution, in contrast to the conventional wisdom, privatization may not decrease the output of the partially-privatized firm. Furthermore, whether privatization improves environmental quality is ambiguous. It will make the environment worse off (better off) if the marginal environmental damage of production is large (small). In addition, the optimal degree of privatization is independent of the marginal damage of pollutant if the environmental damage function is linear. The optimal degree of privatization will be larger (smaller) than that without pollution if the environmental damage function is convex (concave).
Chapter 3 investigates the optimal degree of privatization when there are network externalities in consumption. The impact of the degree of compatibility on the optimal degree of privatization is examined, too. Our major findings are as follows. First, an increase in the degree of network externalities increases the public firm’s output, but may not increase the private firm’s output. Second, the optimal privatization may not decrease against the degree of network externalities. By common wisdom, in the presence of network externalities, the government will reduce the degree of privatization to obtain a greater total output. However, we find that when the products are incompatible with each other and marginal cost increases fast, the optimal privatization will increase with network externalities. Therefore, the optimal privatization with network externalities may be higher than that when network externalities do not exist. Third, whether the optimal privatization with compatibility would be higher than that with incompatibility depends on the increasing speed of marginal cost.
Chapter 4 documents the price competition in a mixed oligopoly which consists of one public firm and one private firm. Three interesting results are obtained. First, the public firm’s price is not necessarily lower than the private firm’s; it can even be higher. Second, in the popular view, privatization will increase the public firm’s price. However, we find that privatization does not assure the increase of the public firm’s price. As the public firm’s cost is high enough, privatization will make the public firm lower its price. Third, contrary to the popular view, we find that if the public firm is less efficient, then the need for the firm to be privatized is less.
Chapter 5 concludes the dissertation and provides some extensions for the future research. |
