Thomas M. Thesing

TOM THESING is the managing partner of Sidley’s office in London and a member of Sidley’s Management and Executive Committees. His principal areas of practice are cross-border M&A, corporate finance and strategic counseling/corporate governance. Tom represents both buyers and sellers of public and private corporations and advises boards of directors on acquisitions, corporate and financial restructuring and corporate governance-related matters. He also has experience with private equity/venture capital investments and joint ventures. Tom has significant experience in transactions in regulated industries, such as financial and payment services, healthcare and life sciences, as well as technology and internet-related businesses. Recognized most for his cross-border experience, virtually all of the transactions Tom leads include parties and businesses in multiple jurisdictions and most frequently across continents, whether North or South America, Europe, Asia, or Africa. 

“His subject matter expertise and holistic understanding of transactions is fantastic.”
Chambers UK 2021

Tom has been recognized for Corporate/M&A and Private Equity Transactions in a number of leading legal publications, including IFLR 1000, Legal 500 UK, Chambers UK, and Chambers Europe.

He has received acknowledgment from numerous industry ranking guides, including:

• Chambers UK 2026 – Ranked as an Eminent Practitioner: Corporate/M&A: £100-800 million where sources note, “He is smart, responsive and polite. He is easy to work with and respected.”
• Chambers Europe 2025 – Ranked as an Eminent Practitioner: Corporate/M&A: Mid-Market.
• Chambers UK 2025 – Ranked as an Eminent Practitioner for Corporate/M&A. Sources note “Tom is a very experienced and calm presence who is very focused on practical solutions and making sure the deal doesn't get sidetracked.”
• Chambers Europe 2024 – Ranked for Corporate/M&A: High-end Capability, where sources note “Thomas is a strong team leader,” and “Thomas always adds meaningful insight and high value to the matters he represents us on.”
• Chambers UK 2024 – Ranked for Corporate/M&A: £100-800 million - London (Firms), with sources commenting “Thomas Thesing is exceptionally experienced, wise, and commercially supportive.”
• Chambers UK 2023 – where clients stated that “Thomas is extremely helpful on strategic as well as purely legal matters. Sophisticated and worldly, and provided excellent support.”
• Chamber UK 2021 – where clients commented “his subject matter expertise and holistic understanding of transactions is fantastic.”
• Legal Business Awards 2021 – Honored as “Private Equity Team of the Year”. 

Further transactions include advising:

• Bradford Airport Logistics LLC on the establishment of an equity joint venture with Flughafen Wien AG.
• Ryan Specialty in its acquisition of Innovisk.
• Argo Blockchain, a global leader in cryptocurrency mining, on its Nasdaq IPO.
• Medline Industries, Inc. in its acquisition of a significant portion of Teleflex Incorporated’s respiratory business for US$286 million.
• Arvelle Therapeutics, a Swiss-based biopharmaceutical company, on its sale to Angelini Pharma for a total cash consideration of up to US$960 million.
• F. Hoffmann-La Roche on its acquisition of Inflazome, a biotech company leading the development of orally available, small molecule NLRP3 inhibitors to address clinical unmet needs in inflammatory diseases by targeting inflammasomes.
• Massachusetts Mutual Life Insurance Company (MassMutual) on the acquisition, with GIC, of Blackstone’s 36% shareholding in Rothesay Life, the largest specialist annuity provider in the UK. Under the terms of the transaction, MassMutual and GIC each became equal 49% shareholders and the transaction valued the group at £5.75 billion.
• Huma Therapeutics, a global digital health technology company, on its acquisition of AstraZeneca’s chronic disease management platform, AMAZE™️.
• AppLovin Corporation on its acquisitions of a Prague-based global developer and publisher of casual, competitive multiplayer mobile games, and a Beijing-based social games and mobile applications developer.
• F. Hoffmann-La Roche on its acquisition of the novel TMEM16A potentiator portfolio, from biopharmaceutical company Enterprise Therapeutics, for treatment of cystic fibrosis and other respiratory diseases.
• MBE WorldWide SpA, a leading third-party provider of shipping, fulfilment, print, and marketing solutions to SMEs, on the growth investment in MBE WorldWide of up to €120 million by funds managed by Oaktree Capital Management LP.
• RoundTable Healthcare Partners in its agreement with Moberg Pharma AB, listed on the main list at NASDAQ OMX Stockholm, to acquire Moberg’s global consumer health business and to fund an equity investment and loan into Moberg Pharma’s MOB-015 development program.
• eBay on its acquisition of Motors.co.uk, to join Gumtree UK, a part of eBay’s classifieds group.
• F. Hoffmann-La Roche on its acquisition of Tusk Therapeutics, a UK-based pre-clinical immuno-oncology company which has developed an antibody with a novel mode of action aimed at depleting regulatory T-cells.
• TransUnion on its acquisition of Callcredit, which was recently named “Private Equity Deal of the Year (Over $1B)” by The M&A Advisor at the 11th Annual International M&A Awards.
• eBay on its acquisition of Ticketbis SA, an international ticket marketplace company headquartered in Spain.
• Northern Trust Corporation on its acquisition of UBS’s fund administration business in Switzerland and Luxembourg.
• Donnelley Financial Solutions on the sale of its language solutions business to SDL plc.
• Archer Daniels Midland on its acquisition of Probiotics International Limited, a UK-based provider of probiotic supplements for human, pet, and production-animal use.
• Rosslyn Data Technologies on its acquisition of Integritie, a British software company that specializes in capturing and organizing unstructured data. 
• PRA Group (formerly known as Portfolio Recovery Associates) on its acquisition of Aktiv Kapital AS, a Norway-based company involved in the acquisition and servicing of non-performing consumer loans throughout Europe and in Canada.
• Schweitzer-Mauduit International (SWM) on its acquisition of certain assets from Smith & Nephew’s Advanced Wound Management division.
• International Game Technology (IGT) in connection with its cross-border merger with GTECH S.p.A., by which IGT and GTECH will combine under a newly formed holding company organized in the United Kingdom.
• Brunswick Corporation in relation to its acquisition of Whale, based in Northern Ireland, a leading manufacturer of water movement and heating systems for the marine, recreational vehicle, industrial, and other markets.
• Baxter International, Inc. on its sale of the commercial vaccines business from its BioSciences group to Pfizer Inc.
• First Data Corporation on the sale of its interest in Electronic Funds Source LLC to private equity firm Warburg Pincus. 
• The Western Union Company on its acquisition of Travelex’s Global Business Payments division, a leading specialist provider of international business payments.
• Third Point LLC on the investment, through its Hellenic Recovery Fund, in Energean Oil & Gas based in Greece.
• Cephalon and Teva Pharmaceuticals in respect of the sale of Middle East, Africa, Asia, and Latin America businesses comprised of certain Mepha and Cephalon brands, along with certain operating assets in Switzerland, which included the demerger of retained businesses in Switzerland and a transfer by way of fonds du commerce in France, to Acino Pharma.
• Massachusetts Mutual Life Insurance in respect of its investments in Rothesay Life, a specialist pension insurer.
• Western Union in a series of transactions through which it acquired the European money transfer network businesses operated by Finint S.r.l. (based in Milan), Angelo Costa S.r.l. (based in Rome), and FEXCO Ltd. (based in Ireland).
• A leading European investment bank in respect of the sale of its interest in the Printemps department store chain in France and a residential real estate portfolio in Germany.  
• FLIR Systems, Inc. in connection with its acquisitions of Raymarine plc (a UK-based marine electronics business for the leisure and light commercial craft market), Traficon International N.V. (a Belgian company specializing in the manufacture of motion detection), and Marine and Remote Sensing Solutions Limited (a company specializing in the provision of security, safety, and data services and solutions for land and maritime assets).
• First Data Corporation in relation to acquisitions and joint venture arrangements for merchant acquiring businesses in Europe and Asia.
• Generac Holdings Inc. in relation to its cross-border acquisitions of Ottomotores UK Limited, including its Ottomotores Mexico and Ottomotores Brazil businesses, and Milan-based Tower Light Srl, a leading developer and supplier of mobile light towers throughout Europe, the Middle East, and Africa.
• International Game Technology in respect of the acquisition of listed Swedish company Entraction AB by way of tender offer.
• Cognizant Technology Solutions on its acquisition of the Indian service center business of UBS AG and numerous other acquisition transactions for Cognizant.
• Medline Industries, Inc. in respect of the acquisition of the International Surgical Products business of CareFusion Corporation.
• eBay on its sale of a controlling interest in Skype to an investment group led by Silver Lake Partners.
• Cephalon on its acquisition of Mepha AG, a European generic and branded generic pharmaceutical company.
• Indigo Capital and Ashby Investments on the sale of Sorex Holdings Limited, a global provider of innovative and patented pest control products with operations in Europe and the United States, to BASF AG.
• Navigant Consulting in respect of its acquisitions and sales of professional service businesses in Europe.