EU Merger Regulation
The law giving the European Commission exclusive review of large EU mergers.
The EU Merger Regulation, Council Regulation 139/2004, gives the European Commission exclusive jurisdiction over concentrations with an EU dimension, defined by combined worldwide and EU-wide turnover thresholds. Deals meeting them are reviewed once in Brussels rather than in each member state, which is the "one-stop shop" principle.
It replaced Regulation 4064/89, which is why older decisions, including the Unilever cases from 2000, cite the earlier regulation.