International R&D Rivalry with Spillovers and Policy Cooperation in R&D Subsidies and Taxes

We have investigated non-cooperative and jointly optimal R&D policies in the framework of Spencer & Brander (1983) in the presence of R&D spillovers. When R&D activities are strategic substitutes and the R&D game exhibits a positive externality, the result of Spencer & Brander (1983) reverses: the non-cooperative policy is a tax while the jointly optimal policy is a subsidy. Moreover, when R&D activities are strategic complements, the usual result of the prisoners' dilemma in the strategic subsidy game does not hold, implying that a welfare intervention is preferable over laissez-faire. When spillovers are sufficiently large, the joint welfare increases with subsidies being higher than those under non-cooperation.