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The Q-Theory of Mergers


  • Boyan Jovanovic
  • Peter L. Rousseau


The Q-theory of investment says that a firm's investment rate should rise with its Q. We argue here that this theory also explains why some firms buy other firms. We find that 1. A firm's merger and acquisition (M&A) investment responds to its Q more -- by a factor of 2.6 -- than its direct investment does, probably because M&A investment is a high fixed cost and a low marginal adjustment cost activity, 2. The typical firm wastes some cash on M&As, but not on internal investment, i.e., the 'Free-Cash Flow' story works, but explains a small fraction of mergers only, and 3. The merger waves of 1900 and the 1920's, `80s, and `90s were a response to profitable reallocation opportunities, but the `60s wave was probably caused by something else.

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  • Boyan Jovanovic & Peter L. Rousseau, 2002. "The Q-Theory of Mergers," NBER Working Papers 8740, National Bureau of Economic Research, Inc.
  • Handle: RePEc:nbr:nberwo:8740
    Note: AP CF EFG PR

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    References listed on IDEAS

    1. Boyan Jovanovic & Peter L. Rousseau, 2001. "Why Wait? A Century of Life before IPO," American Economic Review, American Economic Association, vol. 91(2), pages 336-341, May.
    2. Servaes, Henri, 1991. " Tobin's Q and the Gains from Takeovers," Journal of Finance, American Finance Association, vol. 46(1), pages 409-419, March.
    3. Boyan Jovanovic & Peter L. Rousseau, 2000. "Vintage organization capital," Proceedings, Federal Reserve Bank of San Francisco, issue Apr.
    4. Jensen, Michael C, 1986. "Agency Costs of Free Cash Flow, Corporate Finance, and Takeovers," American Economic Review, American Economic Association, vol. 76(2), pages 323-329, May.
    5. Gregor Andrade & Mark Mitchell & Erik Stafford, 2001. "New Evidence and Perspectives on Mergers," Journal of Economic Perspectives, American Economic Association, vol. 15(2), pages 103-120, Spring.
    6. Hayashi, Fumio & Inoue, Tohru, 1991. "The Relation between Firm Growth and Q with Multiple Capital Goods: Theory and Evidence from Panel Data on Japanese Firms," Econometrica, Econometric Society, vol. 59(3), pages 731-753, May.
    7. Hayashi, Fumio, 1982. "Tobin's Marginal q and Average q: A Neoclassical Interpretation," Econometrica, Econometric Society, vol. 50(1), pages 213-224, January.
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    JEL classification:

    • O3 - Economic Development, Innovation, Technological Change, and Growth - - Innovation; Research and Development; Technological Change; Intellectual Property Rights

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