| 研究実績の概要 |
水道事業のような独占的・寡占的な公営・民営の垂直分割可能な企業ネットワークの理論分析（Berg, Okamura. H.Yane and Yane Shinji, “Efficient performance by companies with mixedownership: Privatization and divestiture of a vertically integrated public monopoly,” Annals of Public and Cooperative Economics, 14 June 2021.）の結果、主として次のような政策的含意を明確にすることができた。
(1) a vertically integrated private monopoly can be more efficient than any combination of mixed companies when there is a sufficiently flat linear (elastic) demand curve and relatively greater (upward sloping) marginal cost for the downstream sector;
(2) an upstream public and downstream public firm can achieve the first best outcome when the downstream firm has constant marginal costs;
(3) a partial privatization of the upstream firm achieves higher welfare than taking that action for the downstream firm. The intuition behind the propositions is provided using standard features of cost and demand.
すなわち、これらの需要および費用パラメータの大小関係に焦点を合わせる十分に合理的な理論的な根拠を確立できたといえる。
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