IDEAS home Printed from
   My bibliography  Save this paper

Vertical Integration in Restructured Electricity Markets: Measuring Market Efficiency and Firm Conduct


  • Erin T. Mansur

    () (School of Management)


Unlike other studies that have found substantial inefficiencies in restructured electricity markets, this paper provides estimates that reveal relatively competitive behavior in the Pennsylvania, New Jersey, and Maryland market. This distinctive conclusion results from using a model that incorporates structural market features and particular production constraints that are not captured in previous studies. First, the vertical integration of firms in the PJM market reduces electricity producers' interest in setting high prices; producers sell wholesale electricity and also are required to buy power, which they provide to their retail customers at set rates. My model reflects this degree of vertical integration of PJM firms. Second, I account for production constraints that result in cost nonconvexities. Measures of price-cost margins based on a commonly used method that does not incorporate these nonconvexities imply that market imperfections during the summer following PJM's restructuring increased procurement costs 51% ($950 million). That method further implies considerable welfare loss as actual production costs exceeded the competitive model's estimates by 12.5%. This paper develops a consistent estimate of competitive production decisions that respect important production constraints, and it presents estimates showing that costs were only 3.4% above competitive levels. Using this new method of estimating production, I compare behavior of two producers that have relatively few retail customers with other firms. Consistent with these vertically integrated firms' incentives, only firms with large net selling positions in the market reduced output relative to competitive production estimates.

Suggested Citation

  • Erin T. Mansur, 2003. "Vertical Integration in Restructured Electricity Markets: Measuring Market Efficiency and Firm Conduct," Yale School of Management Working Papers ysm430, Yale School of Management.
  • Handle: RePEc:ysm:somwrk:ysm430

    Download full text from publisher

    File URL:
    Download Restriction: no

    References listed on IDEAS

    1. Owen Lamont, 1998. "Earnings and Expected Returns," Journal of Finance, American Finance Association, vol. 53(5), pages 1563-1587, October.
    2. Andrew W. Lo & Jiang Wang, 2006. "Trading Volume: Implications of an Intertemporal Capital Asset Pricing Model," Journal of Finance, American Finance Association, vol. 61(6), pages 2805-2840, December.
    3. David Easley & Soeren Hvidkjaer & Maureen O'Hara, 2002. "Is Information Risk a Determinant of Asset Returns?," Journal of Finance, American Finance Association, vol. 57(5), pages 2185-2221, October.
    4. Jushan Bai & Serena Ng, 2002. "Determining the Number of Factors in Approximate Factor Models," Econometrica, Econometric Society, vol. 70(1), pages 191-221, January.
    5. Tarun Chordia, 2001. "Market Liquidity and Trading Activity," Journal of Finance, American Finance Association, vol. 56(2), pages 501-530, April.
    6. Chen, Joseph & Hong, Harrison & Stein, Jeremy C., 2001. "Forecasting crashes: trading volume, past returns, and conditional skewness in stock prices," Journal of Financial Economics, Elsevier, vol. 61(3), pages 345-381, September.
    7. Pastor, Lubos & Stambaugh, Robert F., 2003. "Liquidity Risk and Expected Stock Returns," Journal of Political Economy, University of Chicago Press, vol. 111(3), pages 642-685, June.
    8. Chordia, Tarun & Roll, Richard & Subrahmanyam, Avanidhar, 2000. "Commonality in liquidity," Journal of Financial Economics, Elsevier, vol. 56(1), pages 3-28, April.
    9. Chamberlain, Gary & Rothschild, Michael, 1983. "Arbitrage, Factor Structure, and Mean-Variance Analysis on Large Asset Markets," Econometrica, Econometric Society, vol. 51(5), pages 1281-1304, September.
    10. Connor, Gregory & Korajczyk, Robert A., 1988. "Risk and return in an equilibrium APT : Application of a new test methodology," Journal of Financial Economics, Elsevier, vol. 21(2), pages 255-289, September.
    11. Fama, Eugene F & French, Kenneth R, 1996. " Multifactor Explanations of Asset Pricing Anomalies," Journal of Finance, American Finance Association, vol. 51(1), pages 55-84, March.
    12. Maureen O'Hara, 2003. "Presidential Address: Liquidity and Price Discovery," Journal of Finance, American Finance Association, vol. 58(4), pages 1335-1354, August.
    13. Hiemstra, Craig & Jones, Jonathan D, 1994. " Testing for Linear and Nonlinear Granger Causality in the Stock Price-Volume Relation," Journal of Finance, American Finance Association, vol. 49(5), pages 1639-1664, December.
    14. Simon Gervais, 2001. "The High-Volume Return Premium," Journal of Finance, American Finance Association, vol. 56(3), pages 877-919, June.
    15. Tauchen, George E & Pitts, Mark, 1983. "The Price Variability-Volume Relationship on Speculative Markets," Econometrica, Econometric Society, vol. 51(2), pages 485-505, March.
    16. Connor, Gregory & Korajczyk, Robert A, 1993. " A Test for the Number of Factors in an Approximate Factor Model," Journal of Finance, American Finance Association, vol. 48(4), pages 1263-1291, September.
    17. Guillermo Llorente & Roni Michaely & Gideon Saar & Jiang Wang, 2002. "Dynamic Volume-Return Relation of Individual Stocks," Review of Financial Studies, Society for Financial Studies, vol. 15(4), pages 1005-1047.
    18. Karpoff, Jonathan M., 1987. "The Relation between Price Changes and Trading Volume: A Survey," Journal of Financial and Quantitative Analysis, Cambridge University Press, vol. 22(01), pages 109-126, March.
    19. Jose A. Scheinkman & Wei Xiong, 2003. "Overconfidence and Speculative Bubbles," Journal of Political Economy, University of Chicago Press, vol. 111(6), pages 1183-1219, December.
    20. Michaely, Roni & Vila, Jean-Luc, 1996. "Trading Volume with Private Valuation: Evidence from the Ex-dividend Day," Review of Financial Studies, Society for Financial Studies, vol. 9(2), pages 471-509.
    21. Jonathan B. Berk, 2000. "Sorting Out Sorts," Journal of Finance, American Finance Association, vol. 55(1), pages 407-427, February.
    22. Gallant, A Ronald & Rossi, Peter E & Tauchen, George, 1992. "Stock Prices and Volume," Review of Financial Studies, Society for Financial Studies, vol. 5(2), pages 199-242.
    Full references (including those not matched with items on IDEAS)


    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.

    Cited by:

    1. Mansur, Erin T, 2007. "Upstream Competition and Vertical Integration in Electricity Markets," Journal of Law and Economics, University of Chicago Press, vol. 50(1), pages 125-156, February.
    2. SMEERS, Yves, 2005. "How well can one measure market power in restructured electricity systems ?," CORE Discussion Papers 2005050, Université catholique de Louvain, Center for Operations Research and Econometrics (CORE).
    3. Meade, Richard, 2005. "Electricity Investment and Security of Supply in Liberalized Electricity Systems," Working Paper Series 3859, Victoria University of Wellington, The New Zealand Institute for the Study of Competition and Regulation.
    4. Frank A. Wolak, 2007. "Quantifying the supply-side benefits from forward contracting in wholesale electricity markets," Journal of Applied Econometrics, John Wiley & Sons, Ltd., vol. 22(7), pages 1179-1209.
    5. Anderson, Edward J. & Hu, Xinmin, 2008. "Forward contracts and market power in an electricity market," International Journal of Industrial Organization, Elsevier, vol. 26(3), pages 679-694, May.
    6. Elizabeth Armington & Eric Emch & Ken Heyer, 2006. "The Year in Review: Economics at the Antitrust Division, 2005–2006," Review of Industrial Organization, Springer;The Industrial Organization Society, vol. 29(4), pages 305-326, December.
    7. Weigt, Hannes, 2009. "A Review of Liberalization and Modeling of Electricity Markets," MPRA Paper 65651, University Library of Munich, Germany.
    8. Helman, Udi, 2006. "Market power monitoring and mitigation in the US wholesale power markets," Energy, Elsevier, vol. 31(6), pages 877-904.
    9. Malaguzzi Valeri, Laura, 2006. "Comparison of Electricity Deregulation around the World and Implications for Ireland," Quarterly Economic Commentary: Special Articles, Economic and Social Research Institute (ESRI), vol. 2006(3-Autumn), pages 38-63.

    More about this item

    JEL classification:

    • L94 - Industrial Organization - - Industry Studies: Transportation and Utilities - - - Electric Utilities
    • L13 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - Oligopoly and Other Imperfect Markets

    NEP fields

    This paper has been announced in the following NEP Reports:


    Access and download statistics


    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:ysm:somwrk:ysm430. See general information about how to correct material in RePEc.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (). General contact details of provider: .

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    We have no references for this item. You can help adding them by using this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service hosted by the Research Division of the Federal Reserve Bank of St. Louis . RePEc uses bibliographic data supplied by the respective publishers.