We study the gains from trade in a model with oligopolistic competition, heterogeneous firms and innovation, and provide a formula to decompose the mechanism. The new insight we provide is that market concentration can be a welfare-relevant feature of market power above and beyond markup...

We develop a method to measure the incidence of monopolistic markup distortions in the global economy. Using semi-parametric formulas, we measure how trade modifies the deadweight loss of markups through two channels: (1) trade-induced change in markup dispersion, and (2) international...

We develop a macroeconomic framework in which firms are large and have market power with respect to both products and labor. Each firm maximizes a share-weighted average of shareholder utilities, which makes the equilibrium independent of price normalization. In a one-sector economy, if returns...

We analyze the implications of the decline in labor’s share in national income for optimal Ramsey taxation. It is optimal to accompany the decline in labor share by raising capital taxes only if the labor share is falling because of a decline in competition or other mechanisms that raise the...

The recent fall of labor's share of GDP in numerous countries is well-documented, but its causes are poorly understood. We sketch a "superstar firm" model where industries are increasingly characterized by "winner take most" competition, leading a small number of highly profitable (and low labor...

We assess the consequences for market quality and welfare of different entry regimes and exchange pricing policies in a context of limited market participation. To this end we integrate a two-period market microstructure model with an exchange competition model with entry in which exchanges...

This paper sets up a general oligopolistic equilibrium model with unionized labor markets. By accounting for productivity differences, the model features profit and wage differentials across industries. We use this setting to study the impact of trade liberalization on employment, welfare, and...