石川 城太

This paper incorporates key stylized facts about the transport sector into the conventional international oligopoly model and explores how protectionist policies perform differently when transport costs are endogenous and subject to the backhaul problem (i.e., the imbalance of shipping volume in outgoing and incoming routes). A country’s protectionist policies, which benefit domestic firms and harm foreign firms in the conventional model, can harm domestic firms and benefit foreign firms if carriers avoid the backhaul problem. Protectionist policies may also lead to a facilitating practice. In the absence of the backhaul problem, both domestic and foreign consumers lose from protectionist policies.

We examine how trade liberalization affects South’s incentive to protect intellectual property rights (IPR) in a North–South duopoly model where a low‐cost North firm competes with a high‐cost South firm in the South market. The North firm serves the South market through either exports or foreign direct investment (FDI). The extent of effective cost difference between North and South depends on South’s imitation, which in turn depends on South’s IPR protection and absorptive capacity and North firm’s location choice, all of which are endogenously determined in our model. For a given level of IPR protection, South’s absorptive capacity under exports may be greater than under FDI. Even though innovation is exogenous to the model (and hence unaffected by South’s IPR policy), strengthening IPR protection in South can improve its welfare. The relationship between trade costs and the degree of IPR protection that maximizes South welfare is non‐monotone. In particular, South has an incentive to protect IPR only when trade costs are moderate. When masking technology or licensing is incorporated into the model, however, some protection of IPR may be optimal for South eve

Using the footloose capital model with two countries, this paper studies different impacts of emission taxes and quotas on firm location and global emissions under trade liberalization. If only one country (North) sets a target of emissions, firms may have incentive to relocate to the other country (South). That is, the pollution haven effect could arise. We show that a further decrease in trade costs, given an emission regulation in North, increases firm relocation and global emissions only if trade costs are relatively low. Moreover, compared with emission taxes, emission quotas moderate firm relocation, which results in less pollution haven and hence less global emissions.

We explore the effects of environmental and trade policies with negative consumption externalities when a domestic firm and a foreign rival produce imperfect substitutes and compete in the domestic market. Consumption of the foreign product generates more emissions than that of the domestic product. Emission taxes reduce emissions, harm the foreign firm, but may benefit the domestic firm. Tariffs could mitigate externalities more "effectively" than emission taxes. Consumption subsides provided to the domestic product may raise emissions and worsen domestic welfare. Stringent environmental policies may induce the foreign firm to produce an environmentally friendly good, though environmental damages may increase.

This paper sets out a single monopoly model and examines the effects of various trade policies on domestic, foreign and world economies under both segmented and integrated markets. In the segmented~markets case, the spillover effects which stem from non~constant marginal costs are explicitly dealt with. In the integrated-markets case, trade policies are examined in two different notions of market integration. It is shown that the curvature of demand curves are crucial for results and that trade restrictions taken by one country may benefit the other country and/or the world economy.