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Tone Oeyen


He understands our industry, gives to-the-point advice and is responsive

Chambers Global 2022

Profile details

About Tone Oeyen

Tone specialises in European and Belgian competition law, with a particular focus on cross-border merger control and cartel enforcement.

He also advises on abuse of dominance and state aid, as well as on general EU and international trade law and trade defence measures.

Tone has significant experience of complex merger proceedings before the European Commission and other global authorities, which often include the negotiation of remedies.

His conduct practice covers anti-competitive behaviour in all areas, including issues raised by digital transformation, and he has successfully defended clients in cartel and state aid-related litigation before the Belgian and European courts.

He speaks Dutch, English, French, Spanish and German.

Recent work

  • Advising Siemens on the worldwide merger control proceedings of the proposed transformative combination of Siemens' and Alstom's mobility businesses, which is now widely recognised as a landmark case for the European merger control regime.
  • Advising Boehringer Ingelheim on the global merger control aspects of its $22bn asset swap with Sanofi. The deal, which transformed the parties into global leaders in animal health and consumer healthcare respectively, prompted merger filings in over 20 countries, including a rare triple 'fix-it-first' phase one clearance from the European Commission.
  • Advising Solvay on the global competition law aspects of some of its most recent important business reshaping transactions, including its $5.5bn acquisition of Cytec and its €4.3bn 50:50 joint venture with INEOS.
  • Advising a company's subsidiary Telenet on the competition law aspects of its headline $1.3bn ‘fixed-to-mobile’ acquisition of Belgium’s third-largest mobile network operator, BASE.
  • Advising several clients in the context of cartel investigations by Belgium’s competition authority (the BCA) and ensuing litigation before the Belgian courts, including most recently two clients in their successful defence of the BCA’s appeals before the Belgian Supreme Court in relation to the legality of the BCA’s dawn raids in separate cartel investigations in the travel agents and ports sectors.
  • Advising EMI on the sale of its recorded music division to Vivendi and Universal, and on the acquisition of its music publishing division by an investor group including Sony.



  • New York University School of Law, US (LLM in trade regulation,  2009-2010)
  • Ghent University, Belgium (master of law, summa cum laude, 2007-2009; bachelor of law, cum laude, 2004-2007)