Steve Tonsfeldt

Partner
Full contact info

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

Experience

Boston Celtics Announce $6.1 Billion Sale to Group Led by William Chisholm

March 20, 2025

Cooley advised the Boston Celtics and the Grousbeck family – the majority stakeholders of Boston Basketball Partners, which owns the American professional basketball team – in connection with their agreement to sell the Celtics to an investor group led by William Chisholm.

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Related contacts

Matthew Hemington
Partner, Palo Alto
Steve Tonsfeldt
Partner, Palo Alto
David Silverman
Partner, New York
Gaël Y. Hagan
Special Counsel , Colorado
Alanna Anderson
Associate, Palo Alto
Ryan Fitzgerald
Associate, Palo Alto
Mark Windfeld-Hansen
Senior Counsel, Palo Alto
Todd Gluth
Partner, San Diego
Patrick Sharma
Associate, Santa Monica
Megan Browdie
Partner, Washington, DC
Rubin Waranch
Associate, Colorado
Michael McMahon
Partner, Boston
Rishab Kumar
Partner, Palo Alto
Eric Jensen
Senior Counsel, Palo Alto
Mark Tanoury
Senior Partner, Palo Alto
Rachel Thorn
Of counsel, New York

Related Practices & Industries

Egnyte Announces Majority Investment From GI Partners and TA Associates

February 25, 2025

Cooley advised Egnyte, a provider of secure content collaboration and governance solutions, on its strategic growth investment from GI Partners and TA Associates.

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Related contacts

Eric Jensen
Senior Counsel, Palo Alto
Sepideh Mousakhani
Partner, Palo Alto
Anne Lieberman
Partner, Santa Monica
Steve Tonsfeldt
Partner, Palo Alto
Kealan Santistevan
Associate, Palo Alto
Sangitha Palaniappa
Associate, Palo Alto
Michael Bergmann
Partner, Washington, DC
Brett De Jarnette
Partner, Palo Alto
Patrick Flanagan
Partner, New York
Todd Gluth
Partner, San Diego
Tracy Rubin
Partner, Palo Alto
Stella Sarma
Partner, Brussels
Timothy Shapiro
Partner, Palo Alto
David Silverman
Partner, New York
Ryan Vann
Partner, Chicago
Summer Wynn
Partner, San Diego
Howard Morse
Senior Counsel, Washington, DC
Sharon Connaughton
Special Counsel, Washington, DC
Kristopher Kleiner
Special Counsel, Colorado
Rebecca Ross
Special Counsel, Washington, DC
Karen Tsai
Special Counsel, Washington, DC
Nathan Alamillo
Associate, Santa Monica
Caitlin Breitenbruck
Associate, Seattle
Norma Chayo Dichi
Associate, Washington, DC
Queenie Chen
Associate, Palo Alto
Nikki Chang DiFederico
Associate, Palo Alto
Megan Drill
Associate, San Diego
Jeremy M. Exelbert
Associate, New York
Nathaniel Hearn Jr.
Associate, Chicago
Vicky Kandabarow
Associate, Washington, DC
Nicollette R. Kirby
Associate, Washington, DC
Allison Kutner
Associate, New York
Alexandra Leavy
Associate, New York
Emily Lee
Associate, Palo Alto
Narmada Murugan
Associate, Palo Alto
Michael Pelle
Associate, New York
Katie Stevens
Associate, Palo Alto
Rubin Waranch
Associate, Colorado
Kevin Gurley
Quantitative Analyst, New York
Brian Mitchell
Transactional Quantitative Analyst, San Diego

Related Practices & Industries

Transact Campus Announces $1.6 Billion Sale to Roper Technologies

August 15, 2024

Cooley advised Reverence Capital Partners’ portfolio company Transact Campus, an innovative campus technology and payment solutions company, on a definitive agreement signed by Reverence Capital Partners to sell Transact to Roper Technologies for $1.6 billion.

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Related contacts

David Silverman
Partner, New York
Izzy Lubarsky
Partner, New York
Dave Young
Partner, Santa Monica
Grigor Lynch
Associate, Colorado
Pat O'Connell
Associate, New York
Matthew Choy
Associate, New York
Eileen Marshall
Partner, Washington, DC
David Dalton
Associate, Santa Monica
Megan Browdie
Partner, Washington, DC
Julia R. Brinton
Special Counsel, Washington, DC
Alessandra Murata
Partner, Palo Alto
Tony P. Guan
Associate, Santa Monica
Breanna Qin
Associate, Palo Alto
Keith Berets
Partner, Colorado
Tijana Brien
Partner, Palo Alto
Ross Eberly
Partner, Santa Monica
Patrick Flanagan
Partner, New York
Adam Fleisher
Partner, Washington, DC
Todd Gluth
Partner, San Diego
H Joshua Kotin
Partner, Chicago
Mark Lambert
Partner, Palo Alto
Miriam Petrillo
Partner, Chicago
Obrea Poindexter
Partner, Washington, DC
Sean Ruff
Partner, Washington, DC
Ellie Seber
Partner, Santa Monica
Steve Tonsfeldt
Partner, Palo Alto
Jay Vaughan
Partner, Washington, DC
Bryan Berman
Special Counsel, Colorado
Stacey A. Bradford
Special Counsel, Washington, DC
Shimeng Cheng
Special Counsel, San Francisco
David Hopkins
Special Counsel, Colorado
Kristopher Kleiner
Special Counsel, Colorado
Katherine Lee Carey
Special Counsel, San Diego
Stella Sarma
Partner, Brussels
Grant Schweikert
Special Counsel, Washington, DC
Karen Tsai
Special Counsel, Washington, DC
Steve Andersen
Associate, New York
Chelsea André
Associate, Colorado
Cara Buchicchio
Associate, New York
Umer Chaudhry
Associate, Washington, DC
Norris Kadet
Associate, New York
Allison Kutner
Associate, New York
Calvin Lee
Associate, New York
Eileen Leman
Associate, Los Angeles
Tommi McCarthy
Associate, New York
Zachary Sonenshine
Associate, New York
Stevie Yu
Associate, New York
Andy Zachrich
Associate, San Francisco
Patricia Myers
Paralegal Specialist, Colorado
Rebecca Flake
Higher Education Services Advisor, Washington, DC
Brandon Lefebvre
Quantitative Analyst, Boston

Related Practices & Industries

Cepton Signs Definitive Agreement to Sell to Koito

July 29, 2024

Cooley advised the special committee of the board of directors of Cepton, a Silicon Valley innovator and leader in high-performance light detection and ranging (lidar) solutions, on Cepton’s definitive agreement to be acquired by Koito, a top automotive tier-one supplier.

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Related contacts

Steve Tonsfeldt
Partner, Palo Alto
Jenny Ge
Associate, Santa Monica

Related Practices & Industries

Lacework to Be Acquired by Fortinet

June 10, 2024

Cooley advised Lacework, a data-driven cloud security company, on its definitive agreement to be acquired by Fortinet (Nasdaq: FTNT), the global cybersecurity leader driving the convergence of networking and security.

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Related contacts

Steve Tonsfeldt
Partner, Palo Alto
Mark Tanoury
Senior Partner, Palo Alto
Gaël Y. Hagan
Special Counsel , Colorado
Ross Eberly
Partner, Santa Monica
Xander Lee
Partner, Santa Monica
Blake Martell
Of counsel, San Francisco
Howard Morse
Senior Counsel, Washington, DC
Tracy Rubin
Partner, Palo Alto
David Burns
Special Counsel, Washington, DC
Kristin O'Hanlon
Special Counsel, San Francisco
Helen Luu
Associate, Palo Alto
Allison Peth
Associate, Palo Alto
Breanna Qin
Associate, Palo Alto
Christopher Suhler
Associate, Colorado
Genevieve Lim Urban
Associate, Seattle
Natalie D. Vernon
Associate, Colorado
Jeramie Perez
Senior Paralegal, Palo Alto
Kamya Arora
Associate, Palo Alto

Related Practices & Industries

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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