Our experience in merger review builds from a long tradition of involvement in the development of merger clearance regimes in the United States, Europe and around the world.

WilmerHale has secured clearance for hundreds of mergers, acquisitions and joint ventures in the United States and Europe, and from agencies around the world, including in some of the largest and most complex mergers in recent years. We have also successfully opposed mergers. Our lawyers appear regularly before antitrust and competition authorities in the United States and Europe and have a deep understanding of those agencies. We also have extensive experience with antitrust regulators in China, and rely on a network of established relationships with top antitrust counsel in jurisdictions where we do not have offices, ensuring consistent quality and seamless service around the globe. 

Our senior lawyers have direct involvement in merger cases. Clients benefit from their wealth of experience, judgment and understanding of business needs and common sense. Our experience with a broad range of government agencies offers additional insight and capabilities to assist in all aspects of the merger clearance process. For matters likely to attract congressional attention or foreign investment review, our antitrust lawyers routinely work with lawyers in the firm's leading policy, government affairs and national security practices in the United States, Europe and China to help clients in addressing agency interest in major merger matters.

Mueller, Thomas

Thomas Mueller

Chair, Antitrust and Competition Practice Group

+1 202 663 6766 (t)



  • Representing Regal Entertainment Group in its agreement with Cineworld Group PLC, the UK's largest cinema operator, to acquire Regal, a leading motion picture exhibitor owning and operating one of the largest theater circuits in the United States, for $3.6 billion.
  • Guiding global oilfield service provider Baker Hughes in a worldwide merger review of a proposed $35 billion acquisition by Halliburton, including securing one of the largest breakup fees ever paid, and subsequently on the $32 billion combination with GE Oil & Gas.
  • Representing TUI, the world's largest travel company, in merger control proceedings before the European Commission and the German Federal Cartel Office related to the restructuring of Germany's second largest airline.
  • Advising a leading US physician services provider in its $8 billion merger of equals with a major competitor, and previously on a $680 million acquisition of a major US private ambulance service provider.
  • Representing Danaher Corporation in merger control proceedings in various jurisdictions (including in the United States and Germany) concerning its $4 billion acquisition of molecular diagnostics company Cepheid, and previously in its $14 billion acquisition of Pall Corporation, $2.6 billion merger with NetScout, and $6.8 billion merger with Beckman-Coulter.
  • Representing several global energy companies in German merger control proceedings concerning their planned formation of a joint venture for the construction and operation of the Nord Stream 2 offshore-pipeline connecting Russia and Germany (with an investment of around $10 billion).
  • Representing one of Germany's largest utility companies in merger control proceedings concerning its acquisition of VNG, one of Germany's largest natural gas suppliers.
  • Advising International Paper in its $4.5 billion acquisition of Temple-Inland, its subsequent $710 million sale of its building products division to Georgia-Pacific, and its $2.2 billion acquisition of the pulp assets of Weyerhaeuser.
  • Representing Cisco in obtaining clearance in both the United States and the European Union for its $3 billion acquisition of Tandberg, a matter repeatedly cited by US and European Commission officials as a primary example of transatlantic cooperation.
  • Obtaining FTC clearance for Millennium Pharmaceuticals for its $8.8 billion sale to Takeda—the largest overseas acquisition by a Japanese drug firm.
  • Representing StatoilHydro in its acquisition from ConocoPhillips of the JET petrol station network in Sweden and Denmark (an EU Phase 2 case involving extensive econometric assessments and remedies), and previously in obtaining EU approval of its $30 billion merger with the petroleum activities of Norsk Hydro.