This paper proposes that quality differentiation is an important feature of the operations of multi-product firms. We develop a model in which manufacturers vary product quality across their product range by using inputs of different quality levels. Firms' core competency is in varieties of...

We estimate a structural model of heterogeneous multiproduct firms to examine the sources of firm heterogeneity emphasized in the recent trade and macro literatures. Using Nielsen barcode data on prices and sales, we estimate elasticities of substitution within and between firms, and use the...

We develop a simple model of international trade with heterogeneous firms that is consistent with a number of stylized features of the data. In particular, the model predicts positive as well as zero trade flows across pairs of countries, and it allows the number of exporting firms to vary...

This paper reviews empirical methods used to estimate the impact of trade policies under imperfect competition. We decompose the welfare effects of trade policy into four possible channels: (i) a deadweight loss from distorting consumption and production decisions; (ii) a possible gain from...

Multiproduct firms and product turnover are widespread phenomena. This paper develops a theoretical framework that links advantages in R&D and variable costs with firm's ability to expand its portfolio of products. The framework is then applied to explain systematic differences in product...

I survey the influence of Grossman and Hart's (1986) seminal paper in the field of International Trade. I discuss the implementation of the theory in open-economy environments and its implications for the international organization of production and the structure of international trade flows. I...

This paper reviews the empirical evidence on firm heterogeneity in international trade. A first wave of empirical findings from micro data on plants and firms proposed challenges for existing models of international trade and inspired the development of new theories emphasizing firm...