Do Horizontal Mergers Induce Entry? Evidence from the U.S. Airline Industry

Similar documents
Market Power, Efficiencies, and Entry

Working Paper The value of bluer skies: How much do consumers gain from entry by JetBlue Airways in long-haul US Airline Markets?

Calibration of Normalised CES Production Functions in Dynamic Models

Balancing Competition and Cooperation: Evidence from Transatlantic Airline Markets

Working Paper A methodology for the evaluation of competition policy

Working Paper A Note on Pricing and Efficiency in Print Media Industries

How To Understand The Economics Of Open Source Software

Discussion Paper No The Empirical Assessment of Technology Differences: Comparing the Comparable. Manuel Frondel and Christoph M.

Working Paper Airline alliances, antitrust immunity and market foreclosure

SAP Sourcing/CLM Webcast Query & User/Contact Maintenance Web Service

The Changing Global Egg Industry

Security Vendor Benchmark 2016 A Comparison of Security Vendors and Service Providers

Tax Incentives and the Location of FDI: Evidence from a Panel of German Multinationals

Family Business Financing

Guidelines for Merger Analysis

Online But Still Divided Inequality in Private Internet Use in Germany

Mit einem Auge auf den mathema/schen Horizont: Was der Lehrer braucht für die Zukun= seiner Schüler

Who Chooses Whom? Syndication, Skills and Reputation

IAC-BOX Network Integration. IAC-BOX Network Integration IACBOX.COM. Version English

MERGER GUIDELINES COMPETITION COMMISSION OF PAKISTAN

Innovative network monitoring technologies for hydraulically not separated large zones

Who Are the True Venture Capitalists in Germany?

Search Engines Chapter 2 Architecture Felix Naumann

Incumbent Response to Entry by Low-Cost Carriers in the U.S. Airline Industry

School District Interaction and Policy Innovation

Working Paper Is a Newspaper's Companion Website a Competing Outlet Channel for the Print Version?

Heterogeneous ABAP System Copy Technical Overview

Trade and Technology: New Evidence on the Productivity Sorting of Firms

Registered Cartels in Austria Coding Protocol

Forward Integration and Market Entry Evidence from Natural Gas Markets for Household Customers in Germany

Competition between Railway Operators and Low Cost Carriers in Long-Distance Passenger Transport

Minimum Wages and Competition: The Case of the German Roofing Sector

Connecting GESIS research data and publication information systems

SAP Product Road Map SAP Mobile Documents

The Effects of the Bologna Process on College Enrollment and Drop-out Rates

Antitrust Immunity for Airline Alliances

A Test of the Quality of Concentration Indices

Discussion Paper No IT Capital, Job Content and Educational Attainment. Alexandra Spitz

ALWA-Befragungsdaten verknüpft mit administrativen Daten des IAB (ALWA-ADIAB)

Customer Surveys with SAP Contact Center

Working Paper Immigration and outsourcing: a general equilibrium analysis

Stefan Engelberg (IDS Mannheim), Workshop Corpora in Lexical Research, Bucharest, Nov [Folie 1]

The Role of Structural Common and Country-Specific Shocks in the Business Cycle Dynamics of the G7 Countries

Hüschelrath, Kai; Müller, Kathrin; Bilotkach, Volodymyr. Working Paper The construction of a low cost airline network

Blockholdings and Corporate Governance in the EU Banking Sector

Provided in Cooperation with: ZEW - Zentrum für Europäische Wirtschaftsforschung / Center for European Economic Research

Vergleich der Versionen von Kapitel 1 des EU-GMP-Leitfaden (Oktober 2012) 01 July November Januar 2013 Kommentar Maas & Peither

Bei Fragen zu dieser Änderung wenden Sie sich bitte an Ihren Kundenbetreuer, der Ihnen gerne weiterhilft.

Implementing Data Models and Reports with Microsoft SQL Server

Deploying Regional Jets to Add New Spokes to a Hub. Ian Savage* and Burgess Scott Northwestern University

Blockholdings and Corporate Governance in the EU Banking Sector

Determinants of Self-Reporting Under the European Corporate Leniency Program

Apprenticeship Training What for? Investment in Human Capital or Substitution of Cheap Labour?

Exemplar for Internal Assessment Resource German Level 1. Resource title: Planning a School Exchange

Market Definition, Upward Pricing Pressure, and the Role of Courts: A Response to Carlton and Israel

HORIZONTAL MERGERS Advanced Industrial Organization 1

Making SAP s User Experience Strategy Reality Nis Boy Naeve, Andreas Hauser SAP SE SESSION CODE: UX204

Product Quality and Environmental Standards: The Effect of an International Environmental Agreement on Tropical Timber Trade

Provided in Cooperation with: ZEW - Zentrum für Europäische Wirtschaftsforschung / Center for European Economic Research

The Effect of the Internet on Product Quality in the Airline Industry. Itai Ater (Tel Aviv University) and Eugene Orlov (Compass Lexecon) June 2012

Discussion Paper No Factor Mobility, Government Debt and the Decline in Public Investment. Friedrich Heinemann

Estimating Damages from Price-Fixing The Value of Transaction Data

Registries: An alternative for clinical trials?

Application example AC500 Scalable PLC for Individual Automation Communication between AC500 and KNX network abb

Berufsakademie Mannheim University of Co-operative Education Department of Information Technology (International)

LEARNING AGREEMENT FOR STUDIES

A Gains from Trade Perspective on Macroeconomic Fluctuations

Offshoring and ICT Evidence for German Manufacturing and Service Firms

Determinants of Environmental Innovations in Germany: Do Organizational Measures Matter?

STUDENT HANDBOOK M.A./MBA (USA)

Public and Private Enforcement of Competition Law A Differentiated Approach

Discussion Paper No What Drives the Vacancy Rate for Information Technology Workers? Martin Falk

THE AMERICAN AIRLINEW INDUSTRY AND SOUTHWEST AIRLINES. low profit margins. Within the industry, however, there have been differences in terms of

Project Cost Reporting for PPM

FH im Dialog. Weidener Diskussionspapiere. Financial Benefits of Business Process Management - A critical evaluation of current studies

Does Multipoint Competition amongst European Airlines Lead to a Reduction of Competitive Pressure? Mouyrin Renaud

Discussion Paper No The Effects of Public R&D Subsidies on Firms Innovation Activities: The Case of Eastern Germany

Qihoo v. Tencent: economic analysis of the first Chinese Supreme Court decision under Anti-Monopoly Law

Software / FileMaker / Plug-Ins Mailit 6 for FileMaker 10-13

e-journal of Practical Business Research Business Process Benchmarking Implementierung

July Mergers and Acquisitions Guidelines

PBS CBW NLS IQ Enterprise Content Store

BACKUP EAGLE. Release Notes. Version: Date: 11/25/2011

Insights from the Global Chief Marketing Officer Study

What s Wrong with the Airline Industry? Diagnosis and Possible Cures. Statement of

The fourth international conference on ECONOMICS AND MANAGEMENT OF NETWORKS Sarajevo, 3 to 5 September 2009

Anticipated acquisition by Capital Radio Plc of GWR Group Plc

Open Source Customer Relationship Management Solutions Potential for an Impact of Open Source CRM Solutions on Small- and Medium Sized Enterprises

Wir stellen uns vor We introduce ourselves

AP WORLD LANGUAGE AND CULTURE EXAMS 2012 SCORING GUIDELINES

Update to V10. Automic Support: Best Practices Josef Scharl. Please ask your questions here Event code 6262

A Simulation Method to Measure the Tax Burden on Highly Skilled Manpower

Giving Away the Game? The Impact of the Disclosure Effect on the Patenting Decision

TIn 1: Lecture 3: Lernziele. Lecture 3 The Belly of the Architect. Basic internal components of the Pointers and data storage in memory

Level 2 German, 2014

Use of DB2 purescale with SAP Applications

Application of a Simple Nonparametric Conditional Quantile Function Estimator in Unemployment Duration Analysis

The German Taxpayer-Panel

AnyWeb AG

The Internet of Things Our Strategy and Direction: Driving Customer Value

Transcription:

Discussion Paper No. 13-030 Do Horizontal Mergers Induce Entry? Evidence from the U.S. Airline Industry Patrice Bougette, Kai Hüschelrath, and Kathrin Müller

Discussion Paper No. 13-030 Do Horizontal Mergers Induce Entry? Evidence from the U.S. Airline Industry Patrice Bougette, Kai Hüschelrath, and Kathrin Müller Download this ZEW Discussion Paper from our ftp server: http://ftp.zew.de/pub/zew-docs/dp/dp13030.pdf Die Discussion Papers dienen einer möglichst schnellen Verbreitung von neueren Forschungsarbeiten des ZEW. Die Beiträge liegen in alleiniger Verantwortung der Autoren und stellen nicht notwendigerweise die Meinung des ZEW dar. Discussion Papers are intended to make results of ZEW research promptly available to other economists in order to encourage discussion and suggestions for revisions. The authors are solely responsible for the contents which do not necessarily represent the opinion of the ZEW.

Non-technical summary Merger control has become an important part of antitrust policy in many countries around the world. In an ex-ante assessment of horizontal mergers, antitrust authorities typically have to investigate whether the proposed transaction is likely to lead to a substantial lessening of competition. While the merger as such inevitably leads to an increase in market concentration and is therefore susceptible of increasing both market power and market prices, there are two general countervailing forces: demand-side substitution and supply-side substitution. Demand-side substitution basically refers to the degree consumers would switch to substitutes in case of a price increase post-merger while supply-side substitution assesses whether and how competitors will react to such price increases. In this note, we contribute to the sparse empirical literature on supply-side reactions to a merger, i.e., we investigate whether competitors increase or decrease their entry activity in the aftermath of an increase in market concentration through merger. In particular, we use routelevel data for the America West Airlines US Airways merger (2005) to investigate whether such an effect can be identified empirically. Our results show that both entry-inducing and entry-dissuading effects can be observed depending on the type of affected route and the carrier under investigation. Interestingly, routes with ex-ante greater competition concerns (i.e., routes in which both merging parties competed directly before the merger) do not show increased entry activity. Our results therefore suggest that entry-inducing effects should be treated with caution in merger assessments by competition authorities thereby supporting the key policy conclusions derived in Werden and Froeb (1998) from a theoretical perspective.

Das Wichtigste in Kürze In vielen Ländern der Welt ist die Fusionskontrolle zu einem integralen Bestandteil der Wettbewerbspolitik geworden. Im Rahmen einer ex-ante Untersuchung von horizontalen Fusionsvorhaben untersuchen Wettbewerbsbehörden regelmäßig, ob der geplante Zusammenschluss zu einer wesentlichen Verringerung des Wettbewerbs führt. Während eine horizontale Fusion unweigerlich eine Erhöhung der Marktkonzentration zur Folge hat und damit im Verdacht steht, die Marktmacht der fusionierenden Partei zu erhöhen, existieren zwei Effekte die etwaigen Preissteigerungsanreizen entgegenwirken: nachfrageseitige Substitution und angebotsseitige Substitution. Nachfrageseitige Substitution bezieht sich auf den Anteil an Konsumenten, der im Falle einer Preiserhöhung zu Wettbewerbern wechseln würde, während angebotsseitige Substitution die Frage untersucht, in welchem Ausmaß Wettbewerber auf fusionsbedingte Preiserhöhungen reagieren würden. Mit diesem Kurzbeitrag tragen wir zu der spärlichen empirischen Literatur bei, die sich einer Untersuchung der angebotsseitigen Reaktionen auf eine horizontale Fusion widmet; das heißt, wir gehen der Frage nach, ob Wettbewerber ihre Markteintrittsaktivitäten nach erfolgter Fusion erhöhen oder senken. Konkret nutzen wir Marktdaten auf Streckenebene nach dem Abschluss der America West Airlines US Airways Fusion (2005) um zu untersuchen ob empirische Belege für eine entsprechende Reaktion der Wettbewerber gefunden werden können. Unsere Ergebnisse zeigen, dass sowohl verstärkter Markteintritt als auch reduzierter Markteintritt in der Folge der Fusion beobachtet werden konnten und zwar in Abhängigkeit vom Routentyp und der betrachteten Fluggesellschaft. Interessanterweise zeigt sich weiterhin, dass Streckenmärkte mit ex-ante höherem Preissteigerungspotential das heißt insbesondere Streckenmärkte auf denen die beiden fusionierten Parteien in direktem Wettbewerb standen keine erhöhten Markteintrittsaktivitäten aufweisen. Unsere Ergebnisse legen daher den Schluss nahe, dass Wettbewerbsbehörden im Rahmen von Fusionsuntersuchungen vorgebrachten Argumenten einer marktmachtdisziplinierenden Wirkung von Markteintritten (nach erfolgter Fusion) mit einem gehörigen Maß an Skepsis entgegentreten sollten. In dieser Hinsicht bestätigen unsere Ergebnisse die zentralen theoretischen Erkenntnisse des Beitrags von Werden und Froeb (1998).

DO HORIZONTAL MERGERS INDUCE ENTRY? EVIDENCE FROM THE U.S. AIRLINE INDUSTRY Patrice Bougette, Kai Hüschelrath and Kathrin Müller April 2013 Abstract Theoretical research has investigated the relevance of entry-inducing effects as countervailing factor to a merger-related increase in market power. We use route-level data for the America West Airlines US Airways merger (2005) to investigate whether such an effect can be identified empirically. Our results show that both entry-inducing and entry-dissuading effects can be observed depending on the type of affected route and the carrier under investigation. Keywords Airline industry, merger, entry-inducing effects JEL Class L40, L93 Associate Professor, University of Nice-Sophia Antipolis, GREDEG Law, Economics and Manage-ment Research Group, CNRS UMR 7321, 250 rue Albert Einstein, 06560 Valbonne, France, E-mail: patrice.bougette@gredeg.cnrs.fr; Research Associate, LAMETA CNRS UMR 5474, University Montpellier 1. Head, Competition and Regulation Research Group, ZEW Centre for European Economic Research, P.O. Box 10 34 43, D-68034 Mannheim, Germany, E-mail: hueschelrath@zew.de; Coordinator, MaCCI Mannheim Centre for Competition and Innovation; Assistant Professor for Industrial Organization and Competitive Strategy, WHU Otto Beisheim School of Management, Burgplatz 2, 56179 Vallendar, Germany. Researcher, Competition and Regulation Research Group, ZEW Centre for European Economic Research and MaCCI Mannheim Centre for Competition and Innovation, P.O. Box 10 34 43, D-68034 Mannheim, Germany, E-mail: kathrin.mueller@zew.de.

1 INTRODUCTION Merger control has become an important part of antitrust policy in many countries around the world. In an ex-ante assessment of horizontal mergers, antitrust authorities typically have to investigate whether the proposed transaction is likely to lead to a substantial lessening of competition. While the merger as such inevitably leads to an increase in market concentration and is therefore susceptible of increasing both market power and market prices, there are two general countervailing forces: demand-side substitution and supply-side substitution. Demand-side substitution basically refers to the degree consumers would switch to substitutes in case of a price increase post-merger while supply-side substitution assesses whether and how competitors will react to such price increases. In this note, we contribute to the sparse empirical literature on supply-side reactions to a merger, i.e., we investigate whether competitors increase or decrease their entry activity in the aftermath of an increase in market concentration through merger. In particular, we use routelevel data for the America West Airlines US Airways merger (2005) to investigate whether such an effect can be identified empirically. Our results show that both entry-inducing and entry-dissuading effects can be observed depending on the type of affected route and the carrier under investigation. 2 REVIEW OF THE LITERATURE Even if a merger-induced increase in market concentration is substantial, the merging parties may be unable to exercise market power as long as potential entrants swiftly enter and start producing substitutes. The potential relevance of such so-called entry-inducing effects of horizontal mergers has been discussed from a theoretical perspective in papers by Werden and Froeb (1998), Cabral (2003), Spector (2003) and Marino and Zábojník (2006). In their seminal paper, Werden and Froeb (1998) investigate the role of entry-inducing effects in antitrust policy. Based on mergers in simple Cournot and Bertrand industries, they find that firms only have an incentive to merge if (a) they expect significant efficiencies generated from the merger, or (b) they are aware of substantial entry barriers which allow them to charge supracompetitive prices post-merger. They conclude that antitrust authorities should be rather skeptical with respect to the power of entry to prevent (or reverse) anticompetitive effects of horizontal mergers. Cabral (2003) investigates the entry-inducing effects of mergers in a differentiated Bertrand model and, on the one hand, finds that the possibility of entry 1

subsequent to the merger improves consumer welfare. On the other hand, he shows for the case of a merger to monopoly that post-merger consumer welfare may decrease with a larger size of merger efficiencies; basically because they decrease the probability of entry postmerger and the beneficial effect from the cost-saving passed on to consumers is too weak to overcompensate this detrimental effect on consumer welfare. Furthermore, Spector (2003) investigates the relationship between merger efficiencies and entry in a Cournot context. Interestingly, he finds that any profitable Cournot merger that fails to generate synergies inevitably decreases consumer welfare irrespective of entry conditions. He therefore concludes that such mergers should be blocked without even considering the role of postmerger entry. Last but not least, Marino & Zábojník (2006) focus on the time dimension of entry following a merger. They show that if new entry is relatively fast, the incumbents could not merge to increase their market power. In other words, if a merger is initiated in an industry where new entry would follow relatively quickly, the merger is more likely to generate synergies. Otherwise, it would not be attempted in the first place. Interestingly, they also show that a decrease in exogenous entry costs can increase the incumbent firms incentives to monopolize the market through horizontal merger. 3 THE US AIRWAYS AMERICA WEST AIRLINES MERGER We specifically investigate the role of entry-inducing effects following the horizontal merger between US Airways (US) and America West Airlines (HP) in the domestic U.S. airline industry completed in 2005. Although the last decade has seen a couple of mergers between U.S. airlines, several arguments suggest focusing on the HP-US transaction. First, the merger took place at a time without severe external or internal shocks such as terrorist attacks, economic recession or other larger airline mergers. Second, the networks of both carriers were truly complementary showing only four non-stop route overlaps at the time of the merger. Third, the hubs of both airlines were located quite distant from each other with Phoenix and Las Vegas in case of America West Airlines and Charlotte, Philadelphia, and Pittsburgh in case of US Airways. This characteristic, ceteris paribus, makes one-stop connections a closer substitute to non-stop connections than in cases of closely related hubs. In sum, the merger directly affected 239 domestic airport-pairs in the domestic U.S. airline industry. In the following, we differentiate between the following route categories: non-stop overlaps, one-stop overlaps and no overlaps (see Hüschelrath and Müller, 2013, for a detailed characterization). While non-stop overlaps are characterized by direct competition of both 2

merging airlines in a particular non-stop airport pair, one-stop competition refers to the presence of a direct connection offered by one airline while the other carrier operates a onestop connection between the two airports. Although one-stop connections must be considered a low-quality substitute for a direct flight, it might still constrain the carrier with the direct flight in its price-setting behavior. For the HP-US merger, we have identified 4 routes with a non-stop overlap, 31 routes with a one-stop overlap (7 for US, 24 for HP) and 204 routes with no overlap (147 for US, 57 for HP). 4 DATA Our dataset was constructed by collecting and merging data from several sources. We use airline traffic data for the years from 2005 to 2006 from the U.S. DOT T-100 Domestic Segment database. This data contains monthly domestic non-stop segment data reported by U.S. air carriers when both origin and destination airports are located within the boundaries of the United States and its territories. We use T-100 s information on origin, destination, nonstop distance, available capacity, number of departures, and number of passengers to construct a quarterly panel data-set of non-directional non-stop route airport-pair markets. We drop airline-route observations with less than 12 quarterly departures and airline-route observations which were only served one quarter in the observation period. We add demographic information on the population and the number of establishments of the respective Metropolitan Statistical Areas from the U.S. Bureau of Labor Statistics. 5 EMPIRICAL ANALYSIS For an assessment of possible entry-inducing effects of the merger, we estimate a model in which the dependent variable is the change in the number of carriers other than the merging parties ( # airlines w/o merger parties). Accordingly, we refrain from holding the number of other carriers constant but include the lagged value of this variable since the previous competitive environment should largely determine entry activity of other carriers after exit events. Table 1 reports the results of the fixed-effects regressions of merger s entry-inducing effects one year after the completion of the merger. 3

Table 1: Fixed-effects regressions of merger s entry-inducing effects airlines w/o merger parties Variable coeff. (s.e.) post-merger 0.005 (0.007) post # direct comp. 0.066 (0.090) post # US route (no HP comp.) -0.035*** (0.012) post # US route (HP one-stop comp.) -0.086*** (0.026) post # HP route (no US comp.) -0.009 (0.018) post # HP route (US one-stop comp.) 0.056** (0.027) # airlines w/o merger parties (lag) -0.408*** (0.017) # LCCs (lag) 0.057** (0.029) ln(avg. plane size) -0.084*** (0.030) airport size (max) 0.179*** (0.020) HHI of airport with larger size -0.234*** (0.071) airport siz (max) # HHI of larger airport -0.114*** (0.024) airport size (min) 0.238*** (0.037) HHI of airport with smaller size -0.245*** (0.067) airport siz (min) # HHI of smaller airport -0.193*** (0.050) ln(population) (mean) -0.815*** (0.163) ln(# establ. ) (mean) 0.505*** (0.109) Year 2005-0.010** (0.005) Year 2006-0.009 (0.009) Year 2007 0.001 (0.011) 2nd Quarter 0.006 (0.004) 3rd Quarter -0.011*** (0.004) 4th Quarter 0.011** (0.005) Constant 7.076*** (2.000) Observations 24,045 Routes 1,603 R 2 (within/between/overall) 0.211 0.004 0.021 Notes: Significance levels *** p<0.01, ** p<0.05, * p<0.1, cluster-robust standard errors in parentheses. Hausman test prefers the fixed-effects over the random-effects model. Sources: U.S. DOT, T-100 Domestic Segment Data, Airline Origin and Destination Survey (DB1B), U.S. Census and U.S. Bureau of Labor Statistics, authors calculations. As revealed by Table 1, we do not find an entry-inducing effect for all routes affected by the merger. The same result is found for the sub-set of routes in which both carriers competed on a non-stop basis pre-merger. However, on routes with one-stop competition, we do find a significant entry-inducing effect for HP routes with US one-stop competition but an entrydissuading effect for US routes with HP one-stop competition. On routes with no overlap premerger, we only find a small but significant entry-dissuading effect for routes operated by US. The control variables largely show the expected behavior. The number of competitors (# airlines w/o merger parties) has a negative effect on the change in the number of carriers 4

other than the merging parties while the number of low cost carriers in a particular route (# LCCs) is found to have a positive influence. Furthermore, a negative relationship is also found with respect to average plane size (ln(avg. plane size)) suggesting that the usage of larger airplanes dissuade entry. Turning from route-related to airport-related control variables, we also control for the influence of airport size as measured by the mean of the two endpoint airports passenger share (airport size (max)) as well as airport concentration (measured by the Herfindahl-Hirschman Index (HHI)). As revealed by Table 1, while the relationship between the change in the number of carriers other than the merging parties and airport size is found to be positive and highly significant, the respective coefficients for airport concentration show a clearly negative relationship. Furthermore, two demographic variables on the MSA level enter the analyses which aim to capture demand effects. The population (ln(population force) (mean)) shall capture potential total demand. The number of establishments (ln(# establ.) (mean)) is included to capture the demand of less price-sensitive business people. As revealed by Table 1, while a positive relationship is found for the latter variable, population has a negative effect on the change in the number of carriers other than the merging parties. 6 CONCLUSION We have investigated the entry-inducing effects of the America West-US Airways merger in the domestic US airline industry. Theoretical contributions suggest that mergers might attract new entry thereby foreclosing possibilities of the merged entity to increase prices postmerger. Our empirical results on an airport-pair route basis revealed that the entire merger did not have a significant effect on entry behavior by competitors. However, an analysis of different route categories revealed that routes which were operated by US Airways experienced entry-dissuading effects while routes operated by America West partly show a significant increase of entry activity by competitors. Interestingly, routes with ex-ante greater competition concerns (i.e., routes in which both merging parties competed directly before the merger) do not show increased entry activity. Our results therefore suggest that entryinducing effects should be treated with caution in merger assessments by competition authorities thereby supporting the key policy conclusions derived in Werden and Froeb (1998) from a theoretical perspective. 5

REFERENCES Cabral, L. (2003), Horizontal Mergers with Free-Entry: Why Cost Efficiencies May be a Weak Defense and Asset Sales a Poor Remedy, International Journal of Industrial Organization, 21, 607-623. Hüschelrath, K., K. Müller (2013), Airline Networks, Mergers, and Consumer Welfare, Working Paper, Mannheim. Marino, A., J. Zábojník (2006), Merger, Ease of Entry and Entry Deterrence in a Dynamic Model, Journal of Industrial Economics, 54, 397-423. Spector, D. (2003), Horizontal Mergers, Entry, and Efficiency Defences, International Journal of Industrial Organization, 21, 1591-1600. Werden, G., L. Froeb (1998), The Entry-Inducing Effects of Horizontal Mergers: An Exploratory Analysis, Journal of Industrial Economics, 46, 525-543. 6