Marc J. Melitz

The Impact of Trade on Intra‐Industry Reallocations and Aggregate Industry Productivity

This paper develops a dynamic industry model with heterogeneous firms to analyze the intra-industry effects of international trade. The model shows how the exposure to trade will induce only the more productive firms to enter the export market (while some less productive firms continue to produce only for the domestic market) and will simultaneously force the least productive firms to exit. It then shows how further increases in the industrys exposure to trade lead to additional inter-firm reallocations towards more productive firms. The paper also shows how the aggregate industry productivity growth generated by the reallocations contributes to a welfare gain, thus highlighting a benefit from trade that has not been examined theoretically before. The paper adapts Hopenhayns (1992a) dynamic industry model to monopolistic competition in a general equilibrium setting. In so doing, the paper provides an extension of Krugmans (1980) trade model that incorporates firm level productivity differences. Firms with different productivity levels coexist in an industry because each firm faces initial uncertainty concerning its productivity before making an irreversible investment to enter the industry. Entry into the export market is also costly, but the firms decision to export occurs after it gains knowledge of its productivity. Copyright The Econometric Society 2003.

Endogenous Entry, Product Variety, and Business Cycles

This paper builds a framework for the analysis of macroeconomic fluctuations that incorporates the endogenous determination of the number of producers and products over the business cycle. Economic expansions induce higher entry rates by prospective entrants subject to sunk investment costs. The sluggish response of the number of producers generates a new and potentially important endogenous propagation mechanism for business cycle models. The return to investment determines household saving decisions, producer entry, and the allocation of labor across sectors. Our framework replicates several features of business cycles and predicts procyclical profits even for preference specifications that imply countercyclical markups.

Dynamic Olley-Pakes productivity decomposition with entry and exit

In this paper, we propose an extension of the productivity decomposition method developed by Olley & Pakes (1996). This extension provides an accounting for the contributions of both firm entry and exit to aggregate productivity changes. It breaks down the contribution of surviving firms into a component accounting for changes in the firm-level distribution of productivity and another accounting for market share reallocations among those firms - following the same methodology as the one proposed by Olley & Pakes (1996). We argue that the other decompositions that break-down aggregate productivity changes into these same four components introduce some biases in the measurement of the contributions of entry and exit. We apply our proposed decomposition to the large measured increases of productivity in Slovenian manufacturing during the 1995-2000 period and contrast our results with those of other decompositions. We find that, over a 5-year period, the measurement bias associated with entry and exit is substantial, accounting for up to 10 percentage points of aggregate productivity growth. We also find that market share reallocations among surviving firms played a much more important role in driving aggregate productivity changes.

Monetary Policy and Business Cycles with Endogenous Entry and Product Variety [with Comments and Discussion]

This paper studies the role of endogenous producer entry and product creation for monetary policy analysis and business cycle dynamics in a general equilibrium model with imperfect price adjustment. Optimal monetary policy stabilizes product prices, but lets the consumer price index vary to accommodate changes in the number of available products. The free-entry condition links the price of equity (the value of products) with marginal cost and markups and hence with inflation dynamics. No-arbitrage between bonds and equity links the expected return on shares, and thus the financing of product creation, with the return on bonds, affected by monetary policy via interest rate setting. This new channel of monetary policy transmission through asset prices restores the Taylor Principle in the presence of capital accumulation (in the form of new production lines) and forward-looking interest rate setting, unlike in models with traditional physical capital. We also study the implications of endogenous variety for the New Keynesian Phillips curve and business cycle dynamics more generally, and we document the effects of technology, deregulation, and monetary policy shocks, as well as the second moment properties of our model, by means of numerical examples.

Product Mix and Firm Productivity Responses to Trade Competition

We document how demand shocks in export markets lead French multi-product exporters to re-allocate the mix of products sold in those destinations. In response to positive demand shocks, those French firms skew their export sales towards their best performing products; and also extend the range of products sold to that market. We develop a theoretical model of multi-product firms and derive the specific demand and cost conditions needed to generate these product-mix reallocations. Our theoretical model highlights how the increased competition from demand shocks in export markets .and the induced product mix reallocations - induce productivity changes within the firm. We then empirically test for this connection between the demand shocks and the productivity of multi-product firms exporting to those destinations. We find that the effect of those demand shocks on productivity are substantial .and explain an important share of aggregate productivity fluctuations for French manufacturing.

The Impact of Exports on Innovation: Theory and Evidence

This paper investigates the effect of export shocks on innovation. On the one hand a positive shock increases market size and therefore innovation incentives for all firms. On the other hand it increases competition as more firms enter the export market. This in turn reduces profits and therefore innovation incentives particularly for firms with low initial productivity. Overall the positive impact of the export shock on innovation is magnified for high productivity firms, whereas it may negatively affect innovation in low productivity firms. We test this prediction with patent, customs and production data covering all French manufacturing firms. To address potential endogeneity issues, we construct firm-level export proxies which respond to aggregate conditions in a firm’s export destinations but are exogenous to firm-level decisions. We show that patenting robustly increases more with export demand for initially more productive firms. This effect is reversed for the least productive firms as the negative competition effect dominates. JEL codes ∗Addresses Aghion: Collège de France, LSE and PSE; Bergeaud: Banque de France and PSE; Lequien: Banque de France and PSE; Melitz: Harvard University and NBER. The authors would like to thank, without implicating Daron Acemoglu, Ufuk Akcigit, Elhanan Helpman, Giammario Impullitti, Thierry Mayer, Torsten Persson, Stephen Redding, Thomas Sampson, Dan Trefler, John Van Reenen and participants at the 2017 AEA meeting, the NBER Summer Institute 2017, CIFAR and numerous seminars for useful discussions and advises. This work is supported by a public grant overseen by the French National Research Agency (ANR) as part of the “Investissements d’Avenir” program (reference: ANR-10-EQPX-17 Centre d’accès securise aux donnees – CASD)