In the 1950s and 60s, Japanese and US antitrust authorities occassionally used the degree of concentration to regulate industries. Does regulating firms based on their market shares make theoretical sense? We set up a simple duopoly model with stochastic R&D activities to evaluate market share...

We examine a firm that can license its production technology to a rival when firms are heterogeneous in production costs. We show that a complete technology transfer from one firm to another always increases joint profit under weakly concave demand when at least three firms remain in the...

Housing developments (condos and suburban developments) are not necessarily homogeneous. Developers provide different types of units with various sizes and other characteristics catering to different types of customers. In this paper, we allow local consumption externalities within each...

We consider a public good provision game with voluntary participation. Agents participating in the game provide a public good and pay the fees according to a mechanism (allocation rule), while nonparticipants can free-ride on the participants. We examine how the equilibrium public good provision...

Diamond and Mirrlees (1971) and Dasgupta and Stiglitz (1972) show that production efficiency is achieved under the optimal commodity tax when profit income is zero. Here, we consider the simplest possible model to analyze production efficiency in the presence of profit income: a tax reform...

We propose a theory that explains why international trade can widen a wage gap between top income earners and others and cause job polarization. In the basic model, we consider two symmetric countries in which individuals with different abilities work either as knowledge workers, who develop...

We consider competitive markets for multiple commodities with endogenous formation of one- or two-person households. Within each two-person household, externalities from the partner's commodity consumption and unpriced actions are allowed. Each individual has two types of traits: observable...

This paper proposes a model of two-party representative democracy on a single-dimensional political space, in which voters choose their parties in order to influence the parties' choices of representative. After two candidates are selected as the median of each party's support group, Nature...

In many industries, firms reward their customers for making referrals. We analyze the optimal policy mix of price, advertising intensity, and referral fee for monopoly when buyers choose to what extent to refer other consumers to the firm. We find that the firm uses its referral fee, but not its...

We consider the optimal pricing and referral strategy of a monopoly that uses a simple consumer communication network (a chain) to spread product information. The first-best policy with fully discriminatory position-based referral fees involves standard monopoly pricing and referral fees that...