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This paper introduces the Werden-Froeb Index (WFI) to assist in evaluating merger-specific efficiencies in horizontal mergers. The index measures the weighted average reduction in marginal costs required to restore pre-merger equilibrium prices and quantities after the (full or partial) merger is consummated. The WFI is well defined, objective and robust, and it has relatively low information requirements. We propose to use the index as a natural complement to concentration measures such as the Hirschmann-Herfindahl Index in the assessment of horizontal mergers. Copyright 2008 The Authors. Journal compilation 2008 Blackwell Publishing Ltd. and the Editorial Board of The Journal of Industrial Economics.

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  • Marie Goppelsroeder & Maarten Pieter Schinkel & Jan Tuinstra, 2008. "QUANTIFYING THE SCOPE FOR EFFICIENCY DEFENSE IN MERGER CONTROL: THE WERDEN-FROEB-INDEX -super-," Journal of Industrial Economics, Wiley Blackwell, vol. 56(4), pages 778-808, December.
  • Handle: RePEc:bla:jindec:v:56:y:2008:i:4:p:778-808

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    References listed on IDEAS

    1. Jeremy Bulow & Ming Huang & Paul Klemperer, 1999. "Toeholds and Takeovers," Journal of Political Economy, University of Chicago Press, vol. 107(3), pages 427-454, June.
    2. Levin, Dan & Kagel, John H., 2005. "Almost common values auctions revisited," European Economic Review, Elsevier, vol. 49(5), pages 1125-1136, July.
    3. Jacob K. Goeree & Theo Offerman, 2003. "Competitive Bidding in Auctions with Private and Common Values," Economic Journal, Royal Economic Society, vol. 113(489), pages 598-613, July.
    4. de Frutos, Maria-Angeles & Pechlivanos, Lambros, 2006. "Second-price common-value auctions under multidimensional uncertainty," Games and Economic Behavior, Elsevier, vol. 55(1), pages 43-71, April.
    5. Cantillon, Estelle, 2008. "The effect of bidders' asymmetries on expected revenue in auctions," Games and Economic Behavior, Elsevier, vol. 62(1), pages 1-25, January.
    6. Marco Pagnozzi, 2007. "Sorry Winners," Review of Industrial Organization, Springer;The Industrial Organization Society, vol. 30(3), pages 203-225, May.
      • Marco Pagnozzi, 2003. "Sorry Winners," CSEF Working Papers 108, Centre for Studies in Economics and Finance (CSEF), University of Naples, Italy, revised 09 May 2007.
    7. Milgrom, Paul R & Weber, Robert J, 1982. "A Theory of Auctions and Competitive Bidding," Econometrica, Econometric Society, vol. 50(5), pages 1089-1122, September.
    8. Eric Maskin & John Riley, 2000. "Asymmetric Auctions," Review of Economic Studies, Oxford University Press, vol. 67(3), pages 413-438.
    9. Ian Ayres & Peter Cramton, 1996. "Deficit Reduction Through Diversity: How Affirmative Action at the FCC Increased Auction Competition," Papers of Peter Cramton 96slr, University of Maryland, Department of Economics - Peter Cramton, revised 09 Jun 1998.
    10. Christopher Avery & John H. Kagel, 1997. "Second-Price Auctions with Asymmetric Payoffs: An Experimental Investigation," Journal of Economics & Management Strategy, Wiley Blackwell, vol. 6(3), pages 573-603, September.
    11. Olivier Compte & Philippe Jehiel, 2002. "On the Value of Competition in Procurement Auctions," Econometrica, Econometric Society, vol. 70(1), pages 343-355, January.
    12. Klemperer, Paul, 2002. "How (not) to run auctions: The European 3G telecom auctions," European Economic Review, Elsevier, vol. 46(4-5), pages 829-845, May.
    13. Marco Pagnozzi, 2007. "Bidding to lose? Auctions with resale," RAND Journal of Economics, RAND Corporation, vol. 38(4), pages 1090-1112, December.
    14. Paul Klemperer, 2004. "Auctions: Theory and Practice," Online economics textbooks, SUNY-Oswego, Department of Economics, number auction1, March.
    15. Bikhchandani, Sushil, 1988. "Reputation in repeated second-price auctions," Journal of Economic Theory, Elsevier, vol. 46(1), pages 97-119, October.
    16. Klemperer, Paul, 1998. "Auctions with almost common values: The 'Wallet Game' and its applications," European Economic Review, Elsevier, vol. 42(3-5), pages 757-769, May.
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    Cited by:

    1. Duarte Brito & António Osório & Ricardo Ribeiro & Hélder Vasconcelos, 2015. "Unilateral Effects Screens for Partial Horizontal Acquisitions: The Generalized HHI and GUPPI," Working Papers de Economia (Economics Working Papers) 02, Católica Porto Business School, Universidade Católica Portuguesa.
    2. Brito, Duarte & Ribeiro, Ricardo & Vasconcelos, Helder, 2013. "Quantifying the Coordinated Effects of Partial Horizontal Acquisitions," CEPR Discussion Papers 9536, C.E.P.R. Discussion Papers.
    3. Brito, Duarte & Ribeiro, Ricardo & Vasconcelos, Helder, 2014. "Measuring unilateral effects in partial horizontal acquisitions," International Journal of Industrial Organization, Elsevier, vol. 33(C), pages 22-36.

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