The Wolf at the Door: The Impact of Hedge Fund Activism on Corporate Governance

109 Pages Posted: 6 Sep 2015

See all articles by John C. Coffee

John C. Coffee

Columbia Law School; European Corporate Governance Institute (ECGI); American Academy of Arts & Sciences

Darius Palia

Rutgers University, Newark, School of Business-Newark, Department of Finance & Economics; Columbia University - Law School

Date Written: September 4, 2015


Hedge fund activism has increased almost hyperbolically. Although some view this trend optimistically as a means for bridging the separation of ownership and control, we review the evidence and find it far more mixed. In particular, engagements by activist hedge funds appear to be producing a significant externality: severe cut-backs in long-term investment (and particularly a reduction in investment in research and development) by both the targeted firms and other firms not targeted but still deterred from making such investments.

We begin by surveying the regulatory and institutional developments that have reduced the costs and increased the expected payoff from activism for activist investors. We give particular attention to new tactics (including the formation of “wolf packs” — loose associations of activist funds that do not constitute a “group” under the Williams Act) and new institutional structures (such as the alliance between an activist hedge fund and a strategic bidder struck in the recent Allergan takeover battle).

Then, we survey the empirical evidence on how the investment horizons of firms are changing. Next, we review prior studies on the impact of activism, looking successively at (1) who are the targets of activism?; (2) does hedge fund activism create real value?; (3) what are the sources of gains from activism?; and (4) do the targets of activism experience post-intervention changes in real variables? We find the evidence decidedly mixed on most questions.

Finally, we examine the policy levers that could encourage or curb hedge fund activism and consider the feasibility of reforms (including with respect to the law on insider trading). In particular, we consider possible private ordering responses, including new defensive tactics. Our policy preference is to find the least restrictive alternative.

Keywords: hedge fund, institutional investor, long-term investment, research and development (R&D), Schedule 13D, shareholder activism, wealth transfer, Williams Act, wolf pack

Suggested Citation

Coffee, John C. and Palia, Darius, The Wolf at the Door: The Impact of Hedge Fund Activism on Corporate Governance (September 4, 2015). Columbia Law and Economics Working Paper No. 521. Available at SSRN: or

John C. Coffee (Contact Author)

Columbia Law School ( email )

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European Corporate Governance Institute (ECGI)

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American Academy of Arts & Sciences

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Darius Palia

Rutgers University, Newark, School of Business-Newark, Department of Finance & Economics ( email )

111 Washington Street
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Newark, NJ 07102
United States
973-353-5981 (Phone)
973-353-1233 (Fax)

Columbia University - Law School ( email )

435 W 116th St.
New York, NY 10027
United States

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