Jerome Foncel () (University of Lille (GREMARS)) Marc Ivaldi () (Toulouse School of Economics (IDEI), EHESS and CEPR) Jrisy Motis () (Toulouse School of Economics - EHESS (GREMAQ) and University of Crete)
Abstract
We investigate for the individual and relative accuracy of two major market power tests: the Herfindahl Hirschman Index (HHI), and the merger simulation model of unilateral effects. We propose a methodology to compare the predictive and screening power of both tests by implementing them in a hypothetical economy. We find that when a structural econometric approach is missed (substantive test) the concentration approach (dominance test) is biased upwards. We also find that the substantive test is influenced by the market size or more precisely the market size of the outside good. In particular, when it is large, a decision based on the HHI test would have nothing to do with a decision based on the unilateral effects test. Still, in the overall, the substantive test performs better in capturing the true situation of the market compared to the dominance test of concentration.
Download Info
To download:
If you experience problems downloading a file, check if you have the
proper application to
view it first. Information about this may be contained
in the File-Format links below. In case of further problems read
the IDEAS help
page. Note that these files are not on the IDEAS
site. Please be patient as the files may be large.
Publisher Info
Paper provided by University of Crete, Department of Economics in its series Working Papers with number
0833.