Fjell and Heywood (2004) show that privatization is not necessarily welfare neutral in mixed oligopolies under a production subsidy if firms move sequentially. We find that the neutrality holds for any time structure if instead an output floor is introduced.

We revisit the classic discussion of the endogenous choice of a price or a quantity contract, but in a mixed duopoly. We find that choosing the price contract is a dominant strategy for both firms, whether the goods are substitutes or complements.

This paper investigates how horizontal mergers affect the optimal entry barrier (tax) in the presence of free entry and exit. We show that the government should raise the entry tax when a merger reduces the total number of firms entering.

We investigate a mixed oligopoly with misleading advertising competition. We find that, a welfare-maximizing public enterprise always engages in misleading advertising and that, an increase in the number of firms increases the profit and advertising level of each private firm.

In linear-city models, if firms are allowed (not allowed) to locate outside the linear city, they engage in excessive (insufficient) R&D investments from the normative viewpoint. This implies that the feasible set of locations drastically affects their investments.

I investigate an asymmetric duopoly where a public enterprise must supply the demand it faces, while a private enterprise has no such obligation. I show that such an asymmetric regulation yields the first-best outcome (Walrasian equilibrium).