Rev Ind Organ (2011) 39:1–2
Symposium: The 2010 Horizontal Merger Guidelines:
Roger D. Blair
Published online: 22 July 2011
© Springer Science+Business Media, LLC. 2011
The 1992 Horizontal Merger Guidelines got a much needed facelift, if not an outright
overhaul, in 2010. As an expression of the enforcement philosophy and practice of the
Department of Justice and the Federal Trade Commission, the old Guidelines were
out of date and demanded revision. This is just what they got in 2010. And this is the
subject of the present Symposium.
The point of Section 7 of the Clayton Act is to prevent harm to competition that may
occur as a consequence of a horizontal merger. Section 7 accomplishes this (some-
what imperfectly) by prohibiting mergers that substantially increase concentration
in a market and thereby might substantially lessen competition or tend to create a
Hovenkamp leads off the Symposium with an assessment of how the 2010 Guide-
lines address competitive concerns in four areas: exclusion, restraints on innovation,
unilateral effects, and coordinated effects. In this regard, Willig specifically addresses
unilateral effects in some detail. He develops some interesting results on the upward
price pressure that is associated with mergers and some other extensions. As for coor-
dinated effects, Gayle, Marshall, Marx, and Richard examine this competitive concern
in the 2010 Guidelines.
Long ago, Williamson (1968) showed that efﬁciencies could reduce costs enough
to offset an increase in market power. While efﬁciencies crept into the Guidelines,
they played a minor role. Blair and Haynes address the weight given to merger-
I want to thank Larry White for his kind invitation to organize this Symposium on the 2010 Guidelines.
His patience has been remarkable. The papers collected here provide varied reactions to the 2010
Guidelines. I thank the contributors for their excellent work and cooperation.
R. D. Blair (
Walter J. Matherly Professor, Department of Economics, University of Florida,
P.O. Box 117140, Gainesville, FL 32611, USA