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Imports and Exports at the Level of the Firm: Evidence from Belgium


  • The authors are very grateful to the editor and two anonymous referees for their constructive comments. They also thank George van Gastel, Jean-Marc Troch and the Microeconomic Analysis Service team of the National Bank of Belgium (NBB) for their invaluable help with the construction of the dataset. They would also like to thank, for their helpful comments, participants in seminars at the NBB and CEP. In particular, they are grateful to Holger Breinlich, Emmanuel Dhyne, Luc Dresse, Richard Kneller, Frédéric Lagneaux, Christophe Piette, Stephen Redding, Frédéric Robert-Nicoud, Alessandra Tucci, David Vivet and Alan Winters, for very useful comments and suggestions. Cecile Buydens, Rudy Charles, Edwig Lelie, Ghislain Poullet and Filip Spagnoli are also thanked for their help with various parts of the database.

  • The research results and conclusions expressed are those of the authors and do not necessarily reflect the views of the National Bank of Belgium, OECD or any other institution to which the authors are affiliated. All remaining errors are ours.


This paper explores a newly available panel dataset merging balance sheet and international trade transaction data for Belgium. Both imports and exports appear to be highly concentrated among few firms and seem to have become more so over time. Focusing on manufacturing, we find that facts previously reported in the literature as applying only to exports actually apply to imports too. We note that the number of trading firms diminishes as the number of export destinations or import origins increases. The same is true if we consider the number of products traded. Our results generally point to a process of self-selection in both export and import markets. Also, the productivity advantage of exporters reported in the literature may be overstated because imports were not considered. We find that firms that both import and export are the most productive, followed, in descending order, by importers only, exporters only and non-traders. Our results also show the existence of fixed costs of imports, which appear to be of similar magnitude as those of exports.