The nonlinear GMM-IV estimator of Berry, Levinsohn and Pakes (1995) can suffer from numerical instability resulting in a wide range of parameter estimates and economic implications. This has been reported to depend on technical details such as the choice of the optimization algorithm, starting values, and convergence criteria. We show that numerical approximation errors in the estimator's moment function are the main driver of this instability. With accurate approximation, the estimation approach is well-behaved. We provide a simple method to determine the required number of simulation draws.

We develop a framework to evaluate the impact of market integration, accounting for spillovers between multiple distribution channels. We adapt the standard random coefficients logit demand model to allow for substitution between channels and consumer arbitrage across countries. We apply our framework to the European portable PC market, where geoblocking practices that restrict online cross-border trade have recently been banned. Consumers in high income countries gain most from price convergence, while consumers in other countries may be worse off. The total consumer and welfare gains from online market integration are more modest and mainly due to increased product choice rather than reduced price discrimination. (JEL F13, F14, L13, L63, L81)

Did the Internet make international markets more integrated? To address this question, we study long-term international price differences and their speed of convergence, based on a unique data base for identical goods sold in both online and traditional brick-and-mortar'' distribution channels, covering ten European countries. We find that long-term international price differences are closely comparable between both distribution channels. Furthermore, international price differences converge only slightly faster online than offline, and the differences in the international price differences between online and offline converge at a very fast rate. Finally, regardless of the distribution channel, long-term price differences are lower and converge faster within the same currency union. Our findings imply that online markets are currently not more integrated than traditional markets.

How does cost pass-through to prices depend on the set of products a multi-product firm owns? Using a structural demand model for the Swedish beer market, we simulate equilibrium cost pass-through for varying counterfactual ownership patterns. We find that a firm with a larger number of products in its portfolio and a higher degree of substitutability among these products adopts a lower pass-through of costs. While the direction of results is robust, our simulations show that the muting effect on pass-through is limited when comparing pass-through by stand-alone firms to pass-through under the actual, moderately concentrated market structure.

In this paper we estimate a differentiated products demand model to ask three questions regarding the introduction of e-commerce. First, we ask whether the online distribution channel has increased total sales, or only diverted sales from traditional channels. We find that there is a market expansion effect but also a considerable sales diversion. Second, we ask to which extent consumers and firms benefited from the introduction of the online sales channel. We find that consumers benefited proportionately more, and this is entirely due to the appearance of an additional distribution channel and not due to increased competition. Third, we ask how the online channel has affected European market integration. We find that price differences between the EU countries for identical products are large both in the traditional channel and online. Therefore, the introduction of e-commerce did not influence price levels and international price dispersion in the traditional channel. (C) 2017 The Authors. Published by Elsevier B.V.

We investigate the effect of divestitures on prices and welfare following the Carlsberg–Pripps merger in the Swedish beer market. Both difference-in-difference estimation and simulations using a random coefficients logit model suggest that divestitures are important for dampening price increases. Prices of divested brands fall by around 3% and the predicted price increase for Carlsberg falls from 3 to 1.6% as a result of the divestitures. To guide practice on divestitures, we investigate the role of the recipient and the number and characteristics of the divested products by simulating post-merger outcomes for all relevant cases. We find that in this setting with large multiproduct firms, the competition authority's most effective means to dampen adverse post-merger outcomes are to aim for a small recipient firm and attain a large number of divested products. Enforcing larger divestitures in terms of market share and raising the average cross-price elasticity between the merging parties' divested and retained products strengthen the dampening effect further.

This dissertation consists of four papers in structural empirics that can be broadly categorized into two areas. The first three papers revolve around the structural estimation of demand for differentiated products and several applications thereof (Berry (1994), Berry, Levinsohn and Pakes (1995), Nevo (2000)), while the fourth paper examines the U.S. Treasury yield curve by estimating yields as linear functions of observable state variables (Ang and Piazzesi (2003), Ang et al. (2006)).The central focus of each paper are the underlying economics. Nevertheless, all papers share a common empirical approach. Be it prices of beers in Sweden or yields of U.S. Treasury bonds, it is assumed throughout that the economic variables of interest can be modeled by imposing specific parametric functional forms. The underlying structural parameters are then consistently estimated based on the variation in available data.Consistent estimation naturally hinges on the assumption that the assumed functional forms are correct. Another way of viewing this is that the imposed functions are flexible enough not to impose restrictive patterns on the data that ultimately lead to biased estimates of the structural parameters and thereby produce misleading conclusions regarding the underlying economics.In principle, the danger of misspecification could therefore be avoided by adopting sufficiently flexible functional forms. This, however, typically requires the estimation of a growing number of structural parameters that determine the underlying economic relationships. As an example, we can think of the estimation of differentiated product demand. The key object of interest here is the substitution patterns between the products. That is, we are interested in what happens to the demand of good X and all its rival products, as the price of good X increases. With N products in total, we could collect the product-specific changes in demand in a vector with N entries. It is also possible, however, that the price of any other good Y changes and thereby alters the demands for the remaining varieties. Thus, in total, we are interested in N2 price effects on product-specific demand. With few products, these effects could be estimated directly and the risk of functional misspecification could be excluded (Goolsbee and Petrin (2004)). With 100 products, however, we are required to estimate 10,000 parameters, which rarely, if ever, is feasible. This is the curse of dimensionality.Each estimation method employed in the four papers breaks this curse by imposing functions that depend on relatively few parameters and thereby tries to strike a balance between the necessity to rely on parsimonious structural frameworks and the risk of misspecification. This is a fundamental feature of empirical research in economics that makes it both interesting and challenging.

This dissertation consists of four papers in structural empirics that can be broadly categorized into two areas. The first three papers revolve around the structural estimation of demand for differentiated products and several applications thereof (Berry (1994), Berry, Levinsohn and Pakes (1995), Nevo (2000)), while the fourth paper examines the U.S. Treasury yield curve by estimating yields as linear functions of observable state variables (Ang and Piazzesi (2003), Ang et al. (2006)).The central focus of each paper are the underlying economics. Nevertheless, all papers share a common empirical approach. Be it prices of beers in Sweden or yields of U.S. Treasury bonds, it is assumed throughout that the economic variables of interest can be modeled by imposing specific parametric functional forms. The underlying structural parameters are then consistently estimated based on the variation in available data.Consistent estimation naturally hinges on the assumption that the assumed functional forms are correct. Another way of viewing this is that the imposed functions are flexible enough not to impose restrictive patterns on the data that ultimately lead to biased estimates of the structural parameters and thereby produce misleading conclusions regarding the underlying economics.In principle, the danger of misspecification could therefore be avoided by adopting sufficiently flexible functional forms. This, however, typically requires the estimation of a growing number of structural parameters that determine the underlying economic relationships. As an example, we can think of the estimation of differentiated product demand. The key object of interest here is the substitution patterns between the products. That is, we are interested in what happens to the demand of good X and all its rival products, as the price of good X increases. With N products in total, we could collect the product-specific changes in demand in a vector with N entries. It is also possible, however, that the price of any other good Y changes and thereby alters the demands for the remaining varieties. Thus, in total, we are interested in N2 price effects on product-specific demand. With few products, these effects could be estimated directly and the risk of functional misspecification could be excluded (Goolsbee and Petrin (2004)). With 100 products, however, we are required to estimate 10,000 parameters, which rarely, if ever, is feasible. This is the curse of dimensionality.Each estimation method employed in the four papers breaks this curse by imposing functions that depend on relatively few parameters and thereby tries to strike a balance between the necessity to rely on parsimonious structural frameworks and the risk of misspecification. This is a fundamental feature of empirical research in economics that makes it both interesting and challenging.

Divestitures have received little attention in ex-post evaluations of mergers. In partial remedy we simulate the effects of the Carlsberg-Pripps merger in the Swedish beer market and compare the predicted outcomes with those observed ex-post. There are no important price increases following the merger and prices of divested beers fell. Our merger simulations, that are based on a random coefficients logit model, capture these pricing patterns and suggest that the divestitures were important in limiting price increases. Knowledge of the retailer's markup rules allows us to discard retailer behavior as an explanation for the pricing patterns.