In this paper, we develop a differentiated duopoly model with endogenous cost-reducing R&D and review the argument on welfare effect of price and quantity competition in the presence of technology licensing. We show that the standard conclusion on duopoly (Singh and Vives, 1984) can be completely reversed. Cournot competition induces lower R&D investment than Bertrand competition does. Moreover, Cournot competition leads to lower prices, lower industry profit, higher consumer surplus and higher social welfare than Bertrand competition.

In this paper, we develop a vertically differentiated duopoly model where a high-quality producer competes against a low-quality producer, a la Cournot competition. The high-quality firm has both a new technology and an obsolescent technology. After first deciding whether to license, the firm then chooses which of the two technologies to license. We show that, irrespective of the licensing contract, licensing the new technology is always superior to licensing the obsolescent technology. This finding poses a sharp contrast to the conventional wisdom.

This paper incorporates a durable-good monopoly model and re-examines the argument on licensing contracts. It shows that, from the perspective of the non-producing patent holder, the optimal licensing contract depends on the nature and the degree of the innovations. Specifically, for small cost-reducing or quality-improving innovations, charging a royalty is optimal. For large costreducing or quality-improving innovations, licensing by means of a fee and a royalty is superior to using either alone. However, for the case of horizontal product innovations, using a fee contract is optimal.

We study the dependence of incentives for product innovation on the presence, or absence, of parallel trade. The common assertion is that the presence of parallel trade lowers the incentive for product innovation. Our results support this assertion for some parameter values. However, there are cases in which the presence of parallel trade increases research intensity. For this to occur the innovating firm must already produce and export another good. Further, the new good and the old must be close substitutes and have different transportation costs.

We develop a two-country model of endogenous investment in process innovation by a manufacturer facing competition from parallel imports (PI). We find that the distortions associated with PI inhibit innovation. However, the difference between the manufacturer's expected profits under successful and failed innovation is U-shaped in the cost of engaging in PI. Thus, the reduction in R&D investment depends on both legality of PI and transport costs. The reduction in innovation could harm global welfare, depending on whether the manufacturer was deterring PI with a high wholesale price. If so, banning such trade would raise expected welfare.