Title: Essays on Global Firms
Description: The field of International Trade aims to study the consequences of the spatial disconnection between the activities of production and consumption, which has been allowed by the increasing opening of the economies. However, while most of the history of the field has focused on the role played by production in shaping trade patterns, only recently researchers have emphasized the importance of demand characteristics. This dissertation follows these recent works by containing three essays that specifically study the importance of demand characteristics on export patterns at the microeconomic level. In the first chapter of this dissertation, I explore the importance of the dynamic aspects of demand on the export decisions made by firms. Standard dynamic models of trade identify sunk entry costs as the main export barrier faced by firms. However, these large entry costs are inconsistent with the existence of many small new exporters with low survival rates in foreign markets. In this chapter, I study the role of destination-specific demand dynamics by introducing, in a dynamic model of trade, the idea that firms gradually accumulate consumers in foreign markets.

Estimating the model using export data from individual French firms, I show that this consumer margin is consistent with the dynamics of sales, prices and survival of exporters, but also leads to much lower estimates of the entry costs of exporting - about one third of those estimated in the standard model. Moreover, this change in the nature of trade barriers has important implications at the aggregate level. In contrast to the standard model, this model correctly replicates the slow response of trade to shocks and the increasing contribution of the extensive margin in this response. Finally, I demonstrate using out-of-sample predictions that the model better predicts actual trade responses to an observed shock than the standard model. The second chapter presents a novel instrumental variable strategy to estimate product quality at the micro level using trade data. Written with Gabriel Smagghue from University Carlos III of Madrid, this work develops a new firm-specific instrument, based on variations in exchange rates combined with firm-specific import shares, that delivers, under weak assumptions, consistent estimates of demand elasticity and firm product quality.

Implementing our method using French customs data, we document the reliability of these measures through correlations with firm characteristics and alternative measures of quality. Finally, we use our estimates to document the quality response of French firms when facing low-wage competition on foreign markets. Finally, in the third chapter of this dissertation, I document the positive correlation between the size of a firm and its advertising intensity - measured by the amount spent in advertising as percentages of sales. Taking advantage of firm-level information about advertising expenditures from the Chilean manufacturing census, I show that this correlation holds between firms operating within a similar industry, and is stronger in industries with a larger scope for vertical differentiation. Building on these findings, I develop a model of advertising with heterogeneous firms, based on Arkolakis (2010). In addition to using advertising to inform consumers about the existence of their good, firms can use advertising to affect consumers' valuation of their products.

Consistent with the empirical findings, this latter feature of advertising leads to a positive link between the advertising intensity of a firm and its size. Moreover, this link is amplified by a parameter describing the degree of vertical differentiation of the product.