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.     

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%).     

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.     

Economics at the FTC: The Google-DoubleClick Merger,Resale Price Maintenance,Mortgage Disclosures,and Credit Scoring in Auto Insurance

Economics at the Federal Trade Commission (FTC) supports both the competition and consumer protection missions of the agency. In this year’s essay we discuss competition activity with a summary of our work on the Google-DoubleClick merger and recent activity on resale price maintenance, an area in which FTC economists had done significant prior research. On the consumer policy front, we discuss our study of ways to improve mortgage disclosures to facilitate consumer shopping and competition. Finally, we discuss our study of the effects of credit scoring on prices paid for auto insurance with a focus on the effects of scores on different racial and ethnic groups.     

Economics at the FTC: Hospital Mergers,Authorized Generic Drugs,and Consumer Credit Markets

Economists at the Federal Trade Commission pursue the agency’s competition and consumer protection missions. In this year’s essay, in antitrust, we discuss various aspects of our hospital merger analyses as well as the effects of authorized generic drugs on consumers and competition. In consumer protection, we describe two ongoing studies on the use of credit-based insurance scores to price homeowners insurance, and the accuracy of consumers’ credit reports that are provided by credit bureaus.     

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.     

Forward Contracts,Market Structure and the Welfare Effects of Mergers

We examine how forward contracts affect economic outcomes under generalized market structures. In the model, forward contracts discipline the exercise of market power by making profit less sensitive to changes in output. This impact is greatest in markets with intermediate levels of concentration. Mergers reduce the use of forward contracts in equilibrium and, in markets that are sufficiently concentrated, this amplifies the adverse effects on consumer surplus. Additional analyses of merger profitability and collusion are provided. Throughout, we illustrate and extend the theoretical results using Monte Carlo simulations. We discuss the practical relevance for antitrust enforcement.     

Ex post Merger Evaluation in the U.K. Retail Market for Books

This paper evaluates the price effects of the merger of two major U.K. book retailers. We use a dataset containing monthly scanner data on a sample of 200 books in 50 local markets for four years around the merger. We compare the price changes after the merger in shops located in areas where both chains were present before the merger and in areas where only one chain was present. We also investigate the country‐wide effect of the merger. We find that the merger did not result in any price increase either at the local or at the national level.     

Welfare Analysis of Regulating Mobile Termination Rates in the U.K.

We develop a calibrated simulation model of the U.K. mobile telephony market and use it to analyze the effects of reducing mobile termination rates (MTR's) as recommended by the European Commission. We find that reducing MTR's is likely to increase both consumer surplus and networks' profits. Depending on the strength of call externalities (i.e., benefits to the recipient of a call), social welfare may increase by as much as £1 billion to £4.6 billion per year. We also use the model to estimate the welfare effects of the 2010 merger between Orange and T‐Mobile and find that the merger led to a substantial reduction in consumer surplus.     

Elasticity of demand and behaviour-based price discrimination

Behaviour-based price discrimination (BBPD) is typically analysed in a framework characterised by perfectly inelastic demand. This paper provides a first assessment of the role of demand elasticity on the profit, consumer and welfare effects of BBPD. We show that the demand expansion effect, that is obviously overlooked by the standard framework with unit demand, plays a relevant role. In comparison to uniform pricing, we show that firms are worse off under BBPD, however, as demand elasticity increases the negative impact of BBPD on profits gets smaller. Despite a possible slight increase in the average prices charged over the two periods in comparison to uniform pricing, we show that BBPD boosts consumer surplus and that this benefit is independent of elasticity. In contrast to the welfare results derived under the unit demand assumption, where BBPD is always bad for welfare, the paper shows that BBPD can be welfare enhancing if demand elasticity is sufficiently high.     

On the competitive effects of vertical integration by a research laboratory

An independent research laboratory owns a patented process innovation ready to be used by an industry that produces differentiated goods. We analyze whether the laboratory prefers to license the innovation as an external patentee or to merge with one of the firms in the industry, licensing the innovation as an internal patentee. Under linear demand and Cournot competition, we show first, that the vertical merger is profitable only in the case of small innovations, whereas a merger increases welfare only for significant innovations; second, all profitable vertical mergers reduce welfare. However, some profitable mergers are welfare improving under price competition.     

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].     

One‐Stop Shopping Behavior,Buyer Power and Upstream Merger Incentives

We analyze how consumer preferences for one‐stop shopping affect the (Nash) bargaining relationships between a retailer and its suppliers. One‐stop shopping preferences create ‘demand complementarities’ among otherwise independent products which lead to two opposing effects on upstream merger incentives: first a standard double mark‐up problem and second a bargaining effect. The former creates merger incentives while the later induces suppliers to bargain separately. When buyer power becomes large enough, then suppliers stay separated which raises final good prices. We also show that our result can be obtained when wholesale prices are determined in a non‐cooperative game and under two‐part tariffs.     

Economics at the FTC: Drug and PBM Mergers and Drip Pricing

Economists at the Federal Trade Commission pursue the agency??s competition and consumer protection missions. In this year??s essay, in antitrust, we discuss two recent mergers that involved Rx drugs: First, we describe key elements of the inquiry into the Express Scripts/Medco transaction in the pharmacy benefit management industry. Next, we analyze a merger that involved drugs that are used to treat patent ductus arteriosus: a condition that affects premature babies. On the consumer protection side, we discuss a pricing strategy??drip pricing??that involves the release of price information about a multi-part product over time as the consumer goes through the purchase process.     

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.     

Mergers of complements and entry in innovative industries

I study a merger between producers of complement inputs facing potential entry, with investment by the incumbents in deterministic cost reduction and by the entrants in probabilistic innovation, and then competition in prices. The merger solves Cournot complementarity problems in investment and pricing, which is what makes it profitable but also potentially anti-competitive. When the demand is inelastic the merger harms consumers by reducing R&D of the entrants if the incumbents are efficient enough (always when bundling is adopted). Instead, with a demand elastic enough, the merger increases consumer surplus (even with bundling).     

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.     

A price leadership model for merger analysis

We provide a methodology to simulate the coordinated effects of a proposed merger using data commonly available to antitrust authorities. The model follows the price leadership structure in Miller, Sheu, and Weinberg (2021) in an environment with logit or nested logit demand. The model calibration leverages profit margin data to separately identify the extent of coordinated pricing from marginal costs. Using this framework, we demonstrate how mergers can shift incentive compatibility constraints and thereby lead to adverse competitive effects. The incentive compatibility constraints also affect the extent to which cost efficiencies and divestitures mitigate competitive harms.     

横向合并控制中的资产剥离问题——基于古诺竞争的分析

本文基于古诺竞争构建了一个"三阶段"的博弈模型,分析了外资企业合并控制中的资产剥离问题,探讨了资产剥离的有效性及福利效应。研究发现:在一定条件下,资产剥离能够削弱合并带来的单边效应,改善社会福利,增加合并被批准的可能性。在此基础上,本文探讨了消费者福利标准与社会总福利标准之间的差别,认为提高社会总福利的资产剥离很有可能会降低消费者福利。同时,本文还详细模拟了外资企业与国内企业竞拍剥离资产的过程,认为竞拍结果的不同取决于市场规模的大小以及资产剥离的数量。最后,得出结论并为中国资产剥离的实施提出建议。