Steve Tonsfeldt


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

+1 650 843 5967

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.

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  • Companion Medical Sells to Medtronic 

  • Nanometrics Merges with Rudolph Technologies for $868 Million 

  • Finicity Agrees to Sell to Mastercard for Up to $985 Million 

  • ArcherDX Agrees to Combine With Invitae in $1.4 Billion Deal 

  • TiVo and Xperi to Combine in $3 Billion All-Stock Merger 

  • View all


  • University of California, Berkeley

  • University of Iowa
    BBA, Accounting
    with highest distinction

Admissions & Credentials



  • Berkeley Center for Law, Business and the Economy - Advisory Board

  • Certified Public Accountant

Rankings & Accolades

    Who's Who Legal: Thought Leaders – M&A and Governance (2020)

    Chambers USA: Corporate/M&A – Northern California (2002-2020)

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

    American Lawyer: Dealmaker of the Week

    Best Lawyers in America: Mergers & Acquisitions (2006 – 2019)


+1 650 843 5967 office
+1 650 849 7400 fax

3175 Hanover Street
Palo Alto, CA 94304-1130