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...

In the nineties, average firm size decreased, organisations decentralized, and workers preferences shifted from large to small firms. Our model identifies the economic forces behind this trend. Small firms with little capital at risk are subject to risk-shifting. They realize more of their...