Growth has fallen in the U.S., while firm concentration and profits have risen. Meanwhile, labor's share of national income is down, mostly due to the rising market share of low labor share firms. We propose a theory for these trends in which the driving force is falling firm-level costs of...

We reexamine several bodies of data on the growth of output, labor, and capital, within the context of a model that admits the possibility of an externality to the capital input. The model is an augmented version of Paul Romer's (1987) reformulation of the Solow model. Unlike Romer, however, we...

Will fast growing emerging economies sustain rapid growth rates until they "catch-up" to the technology frontier? Are there incentives for some developed countries to free-ride off of innovators and optimally "fallback" relative to the frontier? This paper models agents growing as a result of...