Thresholds defined on the level and change in the HHI (Herfindahl-Hirschmann Index) applied to market shares seem to be the main instrument to select notified mergers for investigation in both the EU and US. We question the use of such a selection rule in differentiated products industries. We...

One of the central tenets of industrial organisation is that increasing/decreasing market concentration is likely to lead to increased/reduced markups. But does this affect every consumer to the same extent? Previous literature agrees that there can be significant price dispersion even in the...