Leonidas Theodosiou

Leo is a partner on the firm’s “Highly Commended” competition team in London (Legal Business Awards, 2024). He advises on all aspects of UK, EU, and international competition law and competition litigation. Additionally, he counsels clients on FDI matters and the EU regulation of state aid and foreign subsidies.

Leo is praised by clients for his “ability to explain complex legal matters in a way that can be easily understood by non-lawyers,” and for being “extremely skilled and responsive, and [for] bring[ing] a real depth of experience in complex and challenging areas.” It has been noted that he “always goes the extra mile for clients. He really gets to understand the business requirements and commercial context; looking for solutions but also not afraid to tell you the hard truth when you need to hear it.” In relation to merger control, clients say he offers “excellent support and is always on hand during a transaction to offer top class insights which allow for clear and fully informed decision making.” 

In 2021, Leo was featured in the Festival of Talent edition of The Lawyer for his contribution in securing Sainsbury’s victory in the UK Supreme Court in its interchange fee litigation against Visa. He is a member of the Morgan Lewis team that was awarded Behavioural Matter of the Year—Europe, Challenges to CMA Search Warrants, by Global Competition Review in 2018.

Prior to joining Morgan Lewis, Leo spent several years practicing with a Magic Circle law firm, resident in Brussels. In 2018, Leo was seconded to Tata Steel—one of the world’s largest steelmakers—where he served as the organization’s in-house counsel dedicated to antitrust.

Leo holds postgraduate degrees in law from Harvard Law School and the University of Cambridge (Trinity Hall). He has received significant awards and fellowships in recognition of his research and academic achievements, including a Fulbright Fellowship by the US Department of State, and was selected to deliver the 2013 Commencement Speech at Harvard Law School.

Leo is the vice chair of the American Bar Association’s Privacy and Information Security Committee. He frequently speaks and writes about data protection issues, in particular on the interplay between antitrust and data protection.

Leo co-leads the firm’s First Generation Lawyer Network, which seeks to provide “first generation” lawyers with the tools necessary to be successful at all stages of their careers.

Merger & FDI Control

• One of the world’s largest private equity firms on the merger and FDI control aspects of numerous contemplated or completed investments indicatively including:
• the acquisition of a stake in a leading telecommunications company in the context of its Chapter 11 reorganization and recapitalization
• the $5.3 billion SPAC transaction to take public a global travel operator
• the $7.1 billion acquisition of an automotive parts manufacturer
• the $5.2 billion acquisition of a leading air cargo company
• EQT on the UK FDI control aspects of its multi-billion combination with Baring Private Equity Asia
• Yandex on:
• the $3.7 billion combination of the ridesharing businesses with that of Uber in various countries
• its $1 billion acquisition of various interests held by Uber in their formerly joint FoodTech, delivery, and self-driving businesses
• MSP Sports Capital on its acquisition of a stake in McLaren Racing
• Advanz Pharma on various transactions including its acquisition of (i) a portfolio of antiepileptic medicines from Eisai; and (ii) a portfolio of alprostadil products from UCB
• Tata Steel on merger control aspects of various transactions
• Abbott Laboratories on its $2.9 billion acquisition of CFR Pharmaceuticals
• Pfizer on global merger control aspects of various multibillion dollar transactions
• The Carlyle Group on the acquisition of a 36.8% stake from General Electric in Hong Kong listed satellite operator AsiaSat for up to $483 million
• Citigroup in relation to a Phase II merger control investigation into the sale of Citigroup’s retail network in Greece to Alpha Bank
• Hellenic Petroleum and the Greek Privatization Agency in relation to the European Commission’s Phase II investigation into the proposed acquisition of the Greek Gas Transmission System Operator DESFA by SOCAR
• A major games of chance operator in relation to a Phase II merger control investigation into the acquisition of exclusive rights to operate horse-racing betting
• A major investment management company on the acquisition of stakes in a number of Europe’s leading games of chance operators (including Casinos Austria and the Czech lottery company Sazka)

Competition Litigation

• Concordia in connection with the first-ever court challenge of CMA search warrants at the High Court and the Court of Appeal
• Sainsbury’s Supermarkets in relation to its claim against Visa for competition damages arising out of Visa’s UK multilateral interchange fees
• Numerous merchants in the retail, transport, and hospitality industries in relation to their claims for competition damages against Visa and Mastercard arising out of UK and EEA multilateral interchange fees imposed by Visa and Mastercard, respectively
• Focus Pharma on its appeal in the Competition Appeal Tribunal (CAT) against the CMA’s infringement decision alleging that it participated in a market sharing agreement in relation to anti-nausea drug Prochlorperazine
• Mercury Pharma on its appeal in the CAT and then to the Court of Appeal against the CMA’s infringement decision alleging that it abused its market dominance by charging unfair and excessive prices in relation to thyroid drug Liothyronine
• AMCo on its appeal in the CAT and then to the Court of Appeal against the CMA’s infringement decision alleging that it was party to a market exclusion agreement in relation to adrenal insufficiency drug Hydrocortisone
• A leading operator of games of chance in a number of state aid related proceedings before the General Court and the Court of Justice of the European Union (including in T-416/13, Stanleybet v. Commission; T-57/13 and T-58/13, Casino Loutraki, others v. Commission; and subsequent appellate proceedings in C-131/15)

Antitrust Investigations

• A leading defence company on the CMA’s investigation into suspected bid rigging in relation to Home Office contracts for the operation of immigration detention and deportation centers at Heathrow Airport; case closed by the CMA
• AMCo on its defence against a Statement of Objections (SO) and a Supplementary Statement of Objections (SSO) by the CMA regarding an alleged pay-for-delay arrangement with respect to adrenal insufficiency drug Hydrocortisone
• Mercury Pharma on its defence against the CMA’s SO and SSO and Supplementary SSO in relation to alleged unfair and excessive pricing of thyroid drug Liothyronine
• Focus Pharma on its defence against the CMA’s SO in relation to an alleged market exclusion arrangement in respect of anti-nausea drug Prochlorperazine
• Advanz Pharma on its defence against the CMA’s SO in relation to an alleged market sharing arrangement in respect of antibiotic Nitrofurantoin
• A global manufacturing corporation on (i) its internal investigation of suspected antitrust violations; (ii) its application for immunity or leniency to antitrust enforcement agencies; and (iii) designing and implementing its organisation-wide compliance programme
• A global electronics corporation in a major cartel investigation involving immunity applications in multiple jurisdictions in respect of various electronic components

State Aid Control

• A Member State’s privatization agency on state aid control aspects of a number of landmark privatizations, including (i) the extension of the concession for the operation of the country’s largest airport for €1.1 billion; and (ii) the contemplated divestment of the majority of shares in the country’s natural gas transmission incumbent
• Successfully defended Citadele Bank on an in-depth investigation launched by the European Commission concerning allegedly illegal state aid
• An international conglomerate on two state aid investigations into allegedly unlawful infrastructure aid
• A major games of chance operator in relation to multiple state aid investigations
• Spanish, Dutch, and Greek banks which benefitted from state aid on negotiating, implementing and/or amending their restructuring plans in line with EU state aid control rules