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Understanding MACs: Moral Hazard in Acquisitions


  • Ronald J. Gilson
  • Alan Schwartz


The standard contract that governs friendly mergers contains material adverse change (MAC) and material adverse effect (MAE) clauses; these clauses permit a buyer to costlessly cancel the deal if such a change or effect occurs. In recent years, the application of the traditional standard-like MAC and MAE term has been restricted by a detailed set of exceptions that curtails the buyer's ability to exit. The term today engenders substantial litigation and occupies center stage in the negotiation of merger agreements. This article asks what functions the MAC and MAE term serve, what function the exceptions serve, and why the exceptions have arisen only recently. It answers that the terms encourages the target to make otherwise noncontractable synergy investments that would reduce the likelihood of low value realizations, because the term permits the buyer to exit in the event the proposed corporate combination comes to have a low value. The exceptions to the MAC and MAE term impose exogenous risk on the buyer; the parties cannot affect this risk and the buyer is a relatively superior risk bearer. The exceptions have arisen recently because the changing nature of modern deals makes the materialization of exogenous risk a more serious danger than it had been. The modern MAC and MAE terms thus respond to the threat of moral hazard by both parties in the sometimes lengthy interim between executing a merger agreement and closing it. The article empirically examines actual merger contracts and reports results that are consistent with the analysis. Copyright 2005, Oxford University Press.

Suggested Citation

  • Ronald J. Gilson & Alan Schwartz, 2005. "Understanding MACs: Moral Hazard in Acquisitions," Journal of Law, Economics, and Organization, Oxford University Press, vol. 21(2), pages 330-358, October.
  • Handle: RePEc:oup:jleorg:v:21:y:2005:i:2:p:330-358

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    Cited by:

    1. Lau, Stephanie, 2011. "Investment incentives in bilateral trading," Games and Economic Behavior, Elsevier, vol. 73(2), pages 538-552.
    2. repec:kap:jbuset:v:146:y:2017:i:4:d:10.1007_s10551-016-3256-x is not listed on IDEAS
    3. S. Rosenkranz & U. Weitzel, 2005. "Bargaining in Mergers: The Role of Outside Options and Termination Provisions," Working Papers 05-32, Utrecht School of Economics.
    4. Macias, Antonio J. & Moeller, Thomas, 2016. "Target signaling with material adverse change clauses in merger agreements," Journal of Empirical Finance, Elsevier, vol. 39(PA), pages 69-92.
    5. Barry E. Adler, 2012. "Game-Theoretic Bankruptcy Valuation," The Journal of Legal Studies, University of Chicago Press, vol. 41(1), pages 209-238.
    6. Nils Patschureck & Friedrich Sommer & Arnt Wöhrmann, 2015. "Contract design as a risk management tool in corporate acquisitions: theoretical foundations and empirical evidence," Journal of Management Control: Zeitschrift für Planung und Unternehmenssteuerung, Springer, vol. 26(4), pages 279-316, October.
    7. Eric Talley & Drew O'Kane, 2012. "The Measure of a MAC: A Machine-Learning Protocol for Analyzing Force Majeure Clauses in M&A Agreements," Journal of Institutional and Theoretical Economics (JITE), Mohr Siebeck, Tübingen, vol. 168(1), pages 181-201, March.

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