This paper studies the efficiency with which physical capital can be reallocated across sectors. It presents a model of a firm selling specialized capital in a thin resale market. The model predicts that the selling price depends not only on the sectoral specificity of capital, but also on the...

The existing economics literature on international trade agreements focuses on tariff agreements covering trade in goods, and offers an explanation for core features of the GATT. Tariffs play almost no role in services markets, however, and the existing models cannot account for the dramatically...

This paper develops a simple approximation method for computing equilibrium portfolios in dynamic general equilibrium open economy macro models. The method is widely applicable, simple to implement, and gives analytical solutions for equilibrium portfolio positions in any combination or types of...

Product redesigns happen across virtually all types of products. While there is substantial evidence that new varieties of goods increase welfare, there is little evidence on the effect of product redesigns. We develop a model of redesign and exit decisions in a dynamic oligopoly model (a la...

We analyze entry, pricing and product design in a model with differentiated products. Under plausible conditions, entry into an initially monopolized market leads to higher prices for some, possibly all, consumers. Entry can induce a misallocation of goods to consumers, segment the market in a...

We develop a model of repeated product improvements in a continuum of sectors. Each product follows a stochastic progression up a quality ladder. Progress is not uniform across sectors, so an equilibrium distribution of qualities evolves over time. But the rate of aggregate growth is constant....

We investigate optimal consumption, asset accumulation and portfolio decisions in a realistically calibrated life-cycle model with flexible labor supply. Our framework allows for wage rate uncertainly, variable labor supply, social security benefits and portfolio choice over safe bonds and risky...

We study the effects of on-the-job skill accumulation on average hours worked by age and the volatility of hours over the life cycle in a calibrated general equilibrium model. Two forms of skill accumulation are considered: learning by doing and on-the-job training. In our economy with learning...