We study the gains from trade in an economy with oligopolistic competition, firm heterogeneity, and innovation. Oligopolistic competition together with free entry make markups responsive to firm productivity and trade costs. Lowering trade costs reduces markups on domestic sales but increases...

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...

This paper shows that large fiscal multipliers arise naturally from equilibrium unemployment dynamics. In response to a shock that brings the economy into a liquidity trap, an expansion in government spending increases output and causes a fall in the unemployment rate. Since movements in...

This paper shows that large fiscal multipliers arise naturally from equilibrium unemployment dynamics. In response to a shock that brings the economy into a liquidity trap, an expansion in government spending increases output and causes a fall in the unemployment rate. Since movements in...

This paper shows that large fiscal multipliers arise naturally from equilibrium unemployment dynamics. In response to a shock that brings the economy into a liquidity trap, an expansion in government spending increases output and causes a fall in the unemployment rate. Since movements in...

This paper studies a model of equilibrium unemployment in which the ecacy of scal policy increases markedly in times of crises. A sudden rise in pessimism leads households to save rather than to spend, causing a fall in output and rising unemployment But as a persistent rise in unemployment...

This paper proposes a simple iterative method - time iteration - to solve linear rational expectation models. I prove that this method converges to the solution with the smallest eigenvalues in absolute value, and provide the conditions under which this solution is unique. In particular, if...

Dynamic models with inequality constraints pose a challenging problem for two major reasons: Dynamic Programming techniques often necessitate a non established differentiability of the value function, while Euler equation based techniques have problematic or unknown convergence properties. This...

This paper studies a model of optimal redistribution policies in which agents face unemployment risk and in which savings may provide partial self-insurance. Moral hazard arises as job search effort is unobservable. The optimal redistribution policies provide new insights into how an...