Assessing anticompetitive practices in two-sided markets : a comparative analysis of four antitrust proceedings against Booking.com

This paper aims to shed light on the economic tools, as well as the legal-economic reasoning, which are used by different European antitrust authorities to assess the allegedly anticompetitive practices of a platform operating in a two-sided market (2SM). First of all, we show that despite the flourishing literature on 2SM economics, antitrust authorities are still facing major challenges when taking decisions concerning two-sided platforms (2SPs). We suggest that in the lack of a sound economic theory on the effects of abusive behaviour in 2SMs, antitrust authorities have a discretionary power as to what to retain or ignore of a 2SP’s business model. Secondly, we perform a cross-country, comparative analysis of four recent competition proceedings against the 2SP Booking.com and highlight conceptual and practical divergences among antitrust authorities which are bound by and applying a common European legislation towards the same transnational company. Finally, we review the effects of the different authorities' decisions and draw some conclusions as to the effectiveness and appropriateness of the measures which are currently implemented towards 2SPs.