We present a model where accumulation on non-rival knowledge drives growth but where the scale effect, which may be positive or negative, vanishes asymptotically. This result stems from the interaction between technological differentiation and market structure dynamics. Firms are linked to each...

I study the joint determination of market structure and growth in an oligopolistic economy. Firms run in-house R&D programs to produce over time a continuous flow of cost-reducing (incremental) innovations. In symmetric equilibrium, the dispersion of resources across firms prevents the...

I discuss a model of endogenous innovation that brings to the forefront the in-house R&D activity of the modern corporation. In a symmetric oligopoly, firms undertake cost-reducing R&D subject to a research technology with incomplete spillovers. Concentration of sales and R&D resources determine...

Evidence shows that firms build their market position by consistently investing in R&D over time and accumulating knowledge protected by secrecy, patents and other appropriability devices. To explore the macroeconomic implications of this fact, I construct an economy where oligopolistic firms...