Foreign shocks as granular fluctuations

This paper uses a data set covering the universe of French firm-level sales, imports, and exports over the period 1993-2007 and a quantitative multi-country model to study the international transmission of business cycle shocks at both the micro and the macro levels. The largest firms are both important enough to generate aggregate fluctuations (Gabaix 2011), and most likely to be internationally connected. This implies that foreign shocks are transmitted to the domestic economy primarily through the largest firms. We first document a novel stylized fact: larger French firms are significantly more sensitive to foreign GDP growth. We then implement a quantitative framework calibrated to the full extent of observed heterogeneity in firm size, exporting, and importing. We simulate the propagation of foreign shocks to the French economy and report one micro and one macro finding. At the micro level, heterogeneity across firms predominates: 40-85 percent of the impact of foreign fluctuations on French GDP is accounted for by the 'foreign granular residual'-the term capturing the fact that larger firms are more affected by the foreign shocks. At the macro level, firm heterogeneity dampens the impact of foreign shocks, with the GDP responses 10-20 percent larger in a representative firm model compared to the baseline model.