Steve Tonsfeldt

Full contact info

I work with companies on high-stakes, game-changing deals.

About Steve

Steven Tonsfeldt represents public and private companies in domestic and cross-border M&A transactions, contested transactions, hostile takeovers and defense planning. He also advises private investors and their portfolio companies on investment and acquisition transactions, and financial advisors working with companies engaged in transactional matters.

Over the past several years, Steve has led lawyer teams in acquisition transactions having an aggregate value of well over US$100 billion.

Steve has been ranked in Corporate/M&A by Chambers USA for almost 20 years. The American Lawyer has named Steve a Dealmaker of the Week. He has been recognized as a leading corporate lawyer in The Best Lawyers in America, The Legal 500 and Who's Who Legal: Corporate – M&A and Governance. Steve has also been recognized in IFLR1000 as highly regarded in California for private equity and M&A. He has been recognized as a leading dealmaker in America by Lawdragon. 

Steve is a frequent speaker on corporate and M&A topics. He served on the coordinating committee for the American Bar Association's most recent Delaware Business Law Forum. Steve is a member of the advisory board of the Berkeley Center for Law, Business and the Economy.

Prior to law school, Steve worked as a certified public accountant with Deloitte & Touche. He also taught accounting at UC Berkeley's Haas School of Business as a graduate student instructor.


University of California, Berkeley School of Law

University of Iowa
BBA, Accounting, with highest distinction

Rankings and accolades

Chambers USA: Corporate/M&A – California: San Francisco, Silicon Valley & Surro (2003 – 2024)

Lawdragon: 500 Leading Dealmakers in America (2021 – 2023)

Who's Who Legal: Thought Leader – M&A and Governance (2021 – 2023)

IFLR1000: Highly Regarded – Private Equity, M&A (California) (2020 – 2023)

The Legal 500 Recognized Attorney (2016, 2017, 2018, 2019, 2021, 2023)

The Legal 500 M&A Powerlist (2024)

Best Lawyers in America: Mergers & Acquisitions (2006 – 2023)

Memberships and affiliations

Berkeley Center for Law and Business – Executive Advisory Board

Certified Public Accountant