Greg Olsen is a partner in Willkie’s Antitrust & Competition Department. He is based in the Firm’s London office.
Greg has more than 30 years of experience applying EU and UK competition law to mergers, joint ventures, commercial arrangements, market investigations and alleged behavioral violations, including cartels, anticompetitive arrangements and abuse of market power.
Greg advises corporate, private equity and financial institutions in obtaining global FDI and merger control clearances for complex transactions. He has successfully resolved numerous matters before national and European antitrust authorities.
Experience
Prior to joining Willkie, Greg served as an Ordinary Member of the UK Competition Appeal Tribunal. In this judicial appointment, he heard private litigant applications for damages as well as judicial review appeals from decisions of the UK Competition and Markets Authority.
Before that, Greg held the role of Head of the London Antitrust Practice at two international law firms.
- Ranked by Chambers UK for Competition Law; 2025
- Named to The Legal 500 “Hall of Fame”
- Named “Dealmaker of the Year” by Global Competition Review; 2018
- Member, Advisory Board of the Centre for Competition Policy, University of East Anglia
- Chair, Law Society Competition Section; 2008–2009
- Member, ABA Antitrust Magazine Editorial Committee; 2003-2008
- Trustee and Board Member, NZ-UK Link Foundation; 2015 – 2022
Merger Control
- Viasat / Inmarsat (EUMR and UK Phase 2); 2023
- Hitachi Rail / Thales (EUMR and UK Phase 2); 2023
- Dye & Durham / TMG Group (UK Phase 2); 2022
- CD&R / Morrisons (UK Phase 1 remedies); 2022
- Mastercard / Nets (EUMR Phase 1 remedies); 2020
- JLT / Marsh McLennan (EUMR Phase 1 remedies); 2019
- Experian / Clearscore (UK Phase 2); 2019
- Tesco / Booker (UK Phase 2); 2017
- Mastercard / Vocalink (UK Phase 1 remedies); 2017
- TOBC (Electra) / Bowlplex (UK Phase 1 remedies); 2015
- Booker / Makro (UK Phase 2); 2013
Cartel and Other EU and UK Antitrust Investigations
- Advised Mondelez International in resolving the European Commission's investigation into alleged restrictions on cross-border trade in chocolate and other products; 2019-2024
- Advised a private equity fund on CAT appeals related to pharmaceutical products; 2022-2024
- Advised both the Bank of England's Working Group on the Transition from LIBOR to Risk Free Rates and the European Central Bank Working Group on EURIBOR; 2019-2023
- Advised Mastercard in resolving the European Commission's investigation of inter- regional interchange fees and cross-border acquiring rules; 2013-2019
- Advised NBCUniversal in resolving the European Commission's investigation of alleged restrictions on cross-border trade in the licensing of film merchandise; 2017–2020
- Advised NBCUniversal in resolving the European Commission's investigation of alleged restrictions on cross-border access to movies on pay-TV; 2014-2021
- Advised a major bank in connection with LIBOR investigations and other matters; 2015-2019
- Advised Thomson Reuters in resolving the European Commission's investigation of access to Reuters Instrument Codes; 2009-2012
- Advised Mastercard throughout the OFT investigation into Mastercard's UK domestic interchange fees including before the CAT in 2006 when the OFT's decision was set aside; 2001-2006
UK Market Investigations
- Advised NBCUniversal on the UK Competition Commission Movies on Pay TV Market Investigation; 2009-2012
- Advised a major UK bank throughout the SME and retail banking market studies and the Retail Banking Market Investigation; 2010-2017
*Greg advised on some of these matters prior to joining Willkie.
Credentials
Education
University of Oxford, B.C.L., 1990 University of Canterbury, New Zealand, LL.B., 1987