Globalization and multiproduct firms

We present an international trade model with multiproduct firms. Firms are heterogeneously endowed with two types of capabilities that jointly determine the trade-off within firms between managing a large portfolio of products and producing at low marginal cost. The model can explain many of the documented cross-sectional correlations in firm performance measures, including why larger firms are more productive and more diversified, and yet more diversified firms trade at a discount. Globalization is shown to induce heterogeneous responses across firms in terms of scope and productivity, some of which are consistent with existing empirical work, whereas others are potentially testable.