The IMF Working Papers series is designed to make IMF staff research available to a wide audience. With nearly 300 released each year, working papers cover a wide range of theoretical and analytical topics, including balance of payments, monetary and fiscal issues, global liquidity, and national and international economic developments.
Andrei Levchenko, Julian Di Giovanni, and Romain Ranciere
INTERNATIONAL MONETARY FUND
Existing estimates of power laws in firm size typically ignore the impact of international trade. Using a simple theoretical framework, we show that international trade systematically affects the distribution of firm size: the power law exponent among exporting firms should be strictly lower in absolute value than the power law exponent among non-exporting rms. We use a dataset of French firms to demonstrate that this prediction is strongly supported by the data. While estimates of power law exponents have been used to pin down parameters in theoretical and quantitative models, our analysis implies that the existing estimates are systematically lower than the true values. We propose two simple ways of estimating power law parameters that take explicit account of exporting behavior.