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John Orenstein represented hedge funds, individuals, and businesses in a wide variety of litigation for nearly 40 years.

John's specialties included securities, regulatory compliance, employment law, and professional liability. He represented institutional investors in fraud cases, RMBS cases, and bond indenture litigation.

An author and presenter, John has given seminars for the Hennepin County Bar Association, Minnesota Continuing Legal Education, and the National Society of Compliance Professionals.

His community service has included serving as president of Beth El Synagogue, a member of the boards of the Fund for Legal Aid and the Sholom low-income housing facilities, chair of Minnesota J Street, a FINRA arbitrator, and a mediator for the Minnesota Human Rights Department and through the Conflict Resolution Center of Minneapolis.

John continues to serve as a mediator for business and employment litigation.  He is retired, however, from the practice of law.


J.D., Columbia Law School

B.A., Oberlin College, Philosophy with High Honors, Phi Beta Kappa

B.Mus., Oberlin Conservatory of Music, Pi Kappa Lambda 


Ross & Orenstein, Partner 

In-House counsel at financial institutions

U.S. District Court for the District of Columbia, The Honorable William B. Bryant, Law Clerk 


  • State Bar of Minnesota
  • State Bar of New York
  • U.S. Courts of Appeals for the Second and Eighth Circuits
  • U.S. District Court for the District of Minnesota
  • U.S. District Court for the Eastern and Southern District Courts of New York
  • U.S. District Court for the Central District Court of Illinois
  • U.S. District Court for the Eastern District Court of Michigan
  • U.S. Tax Court



  • Federal Bar Association
  • Minnesota State Bar Association
  • Hennepin County Bar Association

John's Practice Areas

  • Accountant Liability

    Greene Espel has extensive experience in a wide variety of disputes and problems confronting accounting firms, including the representation of Big Four, regional, and local accounting firms in audit, tax, and consulting negligence lawsuits, class action securities litigation, review board proceedings, and various federal and state regulatory and criminal matters. 

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  • Commercial Litigation

    Our business litigation practice embraces the wide variety of commercial disputes facing private and public companies today. Areas of particular expertise include intellectual property, antitrust, securities, employment, professional liability, and construction disputes.

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  • Employment Litigation

    Businesses, public institutions, and individuals seek out Greene Espel for representation in a wide range of employment-litigation matters. 

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  • Securities Litigation

    Institutional investors and public companies alike have turned to Greene Espel in high-stakes securities litigation: fraud cases, multi-million-dollar battles over the terms of securities, class actions, shareholder disputes, RMBS, and more. 

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John's Recognition & Awards

  • Selected to Super Lawyers list, Minnesota Super Lawyers (2014-2023)
  • Listed in The Best Lawyers in America (2022-2024)
  • Recognized as Minnesota State Bar Association North Star Lawyer for pro bono service (2019, 2021)

John's Community Involvement

  • Fund for Legal Aid, Board and Executive Committee Member
  • Twin Cities J Street, Chair
  • Upper Mississippi Academy (public charter school), Former Board Member
  • FINRA Arbitrator
  • Beth El Synagogue, Past President 
  • Occasional jazz and cabaret musical performances


August 17, 2023
Best Lawyers Recognizes 16 Greene Espel Attorneys on the 2024 Best Lawyers and Best Lawyers: Ones to Watch Lists
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July 18, 2023
16 Greene Espel Attorneys Recognized on the Minnesota Super Lawyers and Rising Stars Lists
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March 4, 2021
Event (3/4/2021): Intro to Litigation Funding CLE
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