公共社會企業下的民營化政策與中立性

Abstract

本文考慮公營廠商屬於公共社會企業(public social enterprises，文後簡寫為PSE)，即公營廠商目標函數不包含民營廠商利潤，並建構一個包含考慮補貼政策的異質性混合寡占市場模型，來探討民營化中立性定理以及最適的民營化政策。依據本文的研究結果顯示在公營廠商的目標屬於PSE模式下，(1) 不管是長期抑或是短期，也無論是產品同質或異質模型，民營化中立性定理均不成立。此一結果明顯異於傳統目標函數的模式下，僅有在長期之下民營化中立性才會不成立的結果。 (2) 在長期下最適民營化政策為「部分民營化」，此一結果也明顯與傳統文獻，不管是產品同質抑或是產品異質模型其均為完全國營化的政策。(3) 長期下，當產品為同 (異) 質時，最適補貼額為0 (負)。此一結果與傳統模式下，產品為同 (異) 質時，最適補貼額為0 (正) 有所不同。

This paper considers the case where the public firm belongs to public social enterprises (PSE); that is, the objective function of public firm does not include the profits of private firms. A differentiated mixed oligopolistic market model which considers the subsidy policy is constructed. We discuss the privatization neutrality theorem and the optimal privatization policy. The major findings are: supposed that the public firm belongs to the PSE model. (1) No matter whether it is long run or short run, or whether the product is homogeneous or heterogeneous, the privatization neutrality theorem does not hold. This result is obviously different from the traditional result for which privatization neutrality does not hold in the long run. (2) In the long run, the optimal privatization policy is “partial privatization”. This result is also clearly different from the traditional model for which is a fully state-owned policy. (3) In the long run, when the product is homogeneous (heterogeneous), the optimum subsidy is 0 (negative). This result is different from the traditional model in which when the product is homogeneous (heterogeneous), the optimal subsidy is 0 (positive).