Endogenous R&D symmetry in linear duopoly with one-way spillovers

A duopoly model of cost reducing R&D-Cournot competition is extended to study the endogenous timing of R&D strategic investment. Under the assumption that R&D spillovers only flow from the R&D leader to the follower, sequential and simultaneous play at the R&D stage are compared, in order to assess the role of technological externalities in stimulating or attenuating endogenous firm asymmetry. The only timing structure of the R&D stage sustainable as subgame-perfect Nash equilibrium involves simultaneous play and zero spillovers.