Is #concentration rising? @AffeldtPauline, @JoannaPiechucka, #KlausGugler and I use a novel dataset containing information on over 20,000 relevant antitrust markets between 1990-2014 to assess this question: cepr.org/active/publica…. We find quite some heterogeneity. A thread 1/N The extant literature measures #concentration using #industry classifications. Data are mostly aggregated at the national/regional level for all products. Yet, both the #geographic and the #product market definitions should be based on the #substitutability among products. 2/N

This was indeed a fantastic and very insightful panel! Perhaps a summary of the main points can be useful. Thus, a long thread. 1/n

https://twitter.com/digitaleconorg/status/1261010013629415424

All panelists agree: Market power in #digital markets is worrisome. Fiona and Tommaso think that #mergers can worsen this situation and directly harm consumers by killing actual or potential competition, reducing #innovation (either killing the innovation of the target or .. 2/n