Tommaso Valletti: So the practice of economics has become very narrow, and focussing on a couple of unproven models.
If you believed the economics models, then no merger ever hurts prices, because either there is an efficiency or there isn't. He read an "academic meta study of approved mergers" the researcher she only looks at vetted mergers "she does the right thing" in 55% of cases the prices go up (is this our paper, @helenamalikova ?) Tossing a coin is a cheaper way to get this result :-)