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”.
*Only admitted to practice in Illinois. Not admitted to practice in England and Wales.