The effect of mergers on variety in grocery retailing

We study a merger between two Dutch supermarket chains to assess its effect on the depth as well as composition of assortment. We adopt a difference-in-differences strategy that exploits local variation in pre-merger competitive conditions and thus in the merger outcomes. To define our control group, we account for selection on observables through a matching procedure. We observe that, after the merger, the assortment of the merging parties converges in markets where they are not directly competing one with the other. Instead, the merging parties reposition their assortment to avoid cannibalization in the areas where they directly competed before the merger. While the target’s stores reduce the depth of their assortment when in direct competition with the acquirer’s, the latter increase their assortment. This suggests that variety is a strategic variable in retail chains’ response to changes in local competition.     

Recent Developments at DG Competition: 2017/2018

The Directorate General for Competition at the European Commission enforces competition law in the areas of antitrust, merger control, and state aids. This year’s article provides first a general presentation of the role of the Chief Competition Economist’s team and surveys some of the main achievements of the Directorate General for Competition over 2017/2018. The article then reviews: the Google Search (Shopping) case, the role of price discrimination in state aid cases; and the use of counterfactuals in merger cases where alternative transactions might have occurred absent the merger.     

Mergers when firms compete by choosing both price and promotion

We analyze the bias from predicting merger effects using structural models of price competition when firms actually compete using both price and promotion. We extend the standard merger simulation framework to allow for competition over both price and promotion and ask what happens if we ignore promotional competition. This model is applied to the super-premium ice cream industry, where a merger between Nestlé and Dreyer's was challenged by the Federal Trade Commission. We find that ignoring promotional competition significantly biases the predicted price effects of a merger to monopoly (5% instead of 12%). About three-fourths of the difference can be attributed to estimation bias (estimated demand is too elastic), with the remainder due to extrapolation bias from assuming post-merger promotional activity stays constant (instead it declines by 31%).     

Retail Mergers and Food Prices: Evidence from France

This paper analyzes the impact of a merger in the French supermarket industry on food prices. Using consumer panel data, we compare the changes in prices for merging and rival firms in affected and comparison markets. We use a novel definition of affected markets when some firms have a local pricing strategy and others a more centralized pricing strategy. We find that prices increase significantly following the merger, and that the merging firms lose market shares. For the rivals, the price increases are larger in local markets, in which concentration increased and differentiation changed after the merger.     

Collusion Under Imperfect Monitoring with Asymmetric Firms

We explore the effects of asymmetries in capacity constraints on collusion where market demand is uncertain and where firms’ sales and prices are private information. We show that all firms can infer when at least one firm's sales are below some firm‐specific ‘trigger level.’ When firms use this public information to monitor the collusive agreement, price wars may occur on the equilibrium path. Symmetry facilitates collusion but, if price wars are sufficiently long, then the optimal collusive prices of symmetric capacity distributions are lower on average than the competitive prices of asymmetric capacity distributions. We draw conclusions for merger policy.     

Simulating Hospital Merger Simulations*

We perform a Monte Carlo experiment to assess the performance of three hospital merger simulation methods. Our analysis proceeds as follows: (i) specify a theoretical model of hospital markets and use it to generate “true” price effects for many simulated mergers; (ii) for each simulated merger, generate data of the kind commonly available in real-world merger analysis and apply the simulation methods to those data; and (iii) compare the predictions of the simulation methods to the true price effects. All three simulation methods perform reasonably well. We also develop a method for predicting price effects that extends Garmon [2017].     

Proper Treatment of Buyer Power in Merger Review

In this paper, we assess the appropriate treatment of buyer power in merger review. We conclude that, for changes in bargaining outcomes due to a buyer merger to create efficiencies, it must be the case that, post-merger, the parties are able to arrive at a more optimal price schedule, perhaps due to reduced transactions costs. Empirical tests will be important to the evaluation of such efficiencies. We further conclude that, under certain conditions, powerful buyers may be able to prevent higher prices from a merger of suppliers. Once again, empirical tests should guide the evaluation of this merger defense.     

The Competitive Effects of Not-for-Profit Hospital Mergers: A Case Study

Applying conventional horizontal merger enforcement rules to nonprofit hospitals is controversial. Critics contend that the different objective function of not-for-profits entities should mitigate competitive concerns about mergers involving nonprofit hospitals. We analyze a merger that reduced the number of competitors (both nonprofit) in the alleged relevant market from three to two. We find that the transaction was followed by significant price increases; we reject the hypothesis that these price increases reflect higher post-merger quality. This study should help policymakers assess the validity of current merger enforcement rules, especially as they apply to not-for-profit enterprises.     

Pass‐Through and the Prediction of Merger Price Effects

We use Monte Carlo experiments to study how pass‐through can improve merger price predictions, focusing on the first order approximation (FOA) proposed in Jaffe and Weyl [ 2013 ]. FOA addresses the functional form misspecification that can exist in standard merger simulations. We find that the predictions of FOA are tightly distributed around the true price effects if pass‐through is precise, but that measurement error in pass‐through diminishes accuracy. As a comparison to FOA, we also study a methodology that uses pass‐through to select among functional forms for use in simulation. This alternative also increases accuracy relative to standard merger simulation and proves more robust to measurement error.     

Merger Simulation in the Presence of Large Choice Sets and Consumer Stockpiling: The Case of the Bottled Juice Industry

We simulate the price effects of several hypothetical mergers in the shelf-stable bottled juice industry. In doing so, we highlight the effects of consumer stockpiling on demand elasticity estimates and subsequent merger simulations. This task is complicated by a large number of choice alternatives within the bottled juice category. To address this challenge we employ a demand model based on the Distance Metric (DM) approach of Pinkse et al. (Econometrica 70:1111–1153, 2002). We find that merger simulations that do not account for consumer stockpiling behavior underestimate the permanent price changes that are likely to occur due to a merger.      

The Price Effects of the Delta/Northwest Airline Merger

This paper examines the price effects of the merger between Delta Airlines and Northwest Airlines. Empirical analysis finds that, other things equal, the fares for airport-pairs where Delta and Northwest competed with each other prior to the merger did not increase by much following the merger. This result is consistent with the additional finding that the impact of changes in low-cost carrier competition is large while the effect of changes in competition from legacy carriers is slight. Since both Delta and Northwest Airlines are legacy carriers, the results for other legacies suggest that the merger should not have exerted a dramatic impact on fares.     

Modeling Spatial Variation in Housing Prices: A Variable Interaction Approach

The absolute location of each real estate parcel in an urban housing market has a unique location-value signature. Accessibility indices, distant gradients and locational dummies cannot fully account for the influence of absolute location on the market price of housing because there are an indeterminable number of externalities (local and nonlocal) influencing a given property at a given location. Furthermore, the degree to which externalities affect real estate values is not only unique at each location but highly variable over space. Hence, absolute location must be viewed as interactive with other determinants of housing value. We present an interactive variables approach and test its ability to explain price variations in an urban residential housing market. The statistical evidence suggests that the value of location, as embodied in the selling price of housing units, may not be separable from other determinants of value. It is recommended that housing valuation models, therefore, be specified to allow site, structural and other independent attributes to interact with absolute location—{ x , y } coordinates—when accounting for intraurban variation in the market price of residential housing. This approach is especially useful when estimating the value of housing for geographic areas where very little is known a priori about the neighborhoods or submarkets.     

Cross‐Border Mergers and Market Segmentation

This paper shows that cross‐border mergers are more likely to occur in industries which serve multiple segmented markets rather than a single integrated market, given that cost functions are strictly convex. The product price rises in the market where an acquisition is made but falls in the other, decreasing the acquisition price of other firms (in contrast to the results in the existing merger literature on integrated markets). Although the sum of consumer surplus across the countries may rise in response to a given acquisition, one of the countries gains at the expense of the other.     

Upward pricing pressure in two-sided markets: Incorporating rebalancing effects

In two-sided markets it is important to consider rebalancing effects following a merger, i.e. the impact of a change in margin on one side of the market, either due to a price change or to efficiency gains, on the pricing incentives on the other side. We propose modified versions for the indices of pricing pressure (UPP and GUPPI) that take this into account. We show that in two-sided markets where the cross-group externalities are positive the upward pricing pressure will typically be overstated if the rebalancing effect is ignored. Our approach explains why competition agencies should look at both sides of the market when assessing platform mergers.     

Merger Policy at the Margin: Western Refining’s Acquisition of Giant Industries

In May 2007, a United States District Court declined to grant the Federal Trade Commission a preliminary injunction that would have blocked the merger of two petroleum refiners that served Albuquerque, New Mexico, and surrounding areas. This study compares estimates of the post-merger price effect to the price effects that were predicted by economic experts on both sides of the case. I find little scope to interpret the evidence as consistent with an anticompetitive post-merger price effect. I also highlight the difficulties that are involved in econometrically identifying small effects even with an abundance of pricing data.     

A Treatment Effect Method for Merger Analysis with an Application to Parking Prices in Paris

We propose a method of building control groups for retrospective merger evaluation. The procedure involves two parameters: a distance or radius, and an ‘order of exposure’ reflecting the notion that a merger can affect an outlet in a more or less direct way. We implement the method of estimating the price effect of a merger in the Paris parking market and illustrate the consequences of including indirectly exposed outlets in the control group. The methodology applies to any industry with spatial competition and allows one to check the sensitivity of the results to the choice of the control group.     

Consequences of model choice in predicting horizontal merger effects

How practitioners model competition influences the predicted effects of a merger. We show how a Bertrand price setting and a second score auction model can be nested within a general bargaining framework. Through numerical simulations, we then show how the predicted merger effects vary with model choice, and that two commonly used strategies for obtaining demand parameters can yield markedly different outcomes across the models. Finally, we show how model and calibration strategy choices affect the magnitude of predicted harm in the 2012 Bazaarvoice/PowerReviews merger.     

The determinants of merger waves: An international perspective

One of the most conspicuous features of mergers is that they come in waves that are correlated with increases in share prices and price/earnings ratios. We use a natural way to discriminate between pure stock market influences on firm decisions and other influences by examining merger patterns for both listed and unlisted firms. If “real” changes in the economy drive merger waves, as some neoclassical theories of mergers predict, both listed and unlisted firms should experience waves. We find significant differences between listed and unlisted firms as predicted by behavioral theories of merger waves.     

The Ethiopian Commodity Exchange and spatial price dispersion

In this article, we study the impact of an institutional intervention on market efficiency in Ethiopia. More specifically, we analyze to what extent the Ethiopian Commodity Exchange (ECX) in combination with regional warehouses have contributed to a reduction in price spreads between regional markets. Our hypothesis is that warehouses connected to the ECX reduce the dispersion between export prices and local retail prices in different coffee growing areas, as well as the dispersion between export prices and local retail prices in different coffee growing areas. By doing so, the ECX has the potential to improve the market efficiency. To identify the causal effect, we combine retail price data with information on the gradual rollout of warehouses connected to the ECX from 2007 to 2012. Our results suggest that, when two markets both have access to an operating warehouse, the average price spread is 0.86–1.78 ETB lower than it is for markets where at least one part lacks warehouse access. This is a substantial reduction considering that the average price spread over the full period is 3.33 ETB. The main results are robust to various econometric specifications, and our analysis thus suggests that local warehouses connected to the ECX have indeed improved market efficiency.