The article looks at European merger control from 1990 to 2014. It examines how factors like market dominance, rising concentration, entry barriers, and foreclosure affect merger policy. Traditional models may overestimate these effects. Dominance is linked to competitive concerns, especially in complex mergers and markets with higher post-merger concentration. Competitive worries also rise with increasing concentration, entry barriers, and foreclosure. These factors consistently impact competitive concerns regardless of market definition or time period.