Alison Plessman

Hueston Hennigan

Partner

523 West 6th
St., Suite 400
Los Angeles, CA 90014

+1 213.788.4542

Litigation Star

English


Jurisdiction:

California

Practice area:

Commercial
Intellectual property
Securities


Consistently recognized as one of the “Best Lawyers in America,” Alison Plessman delivers successful outcomes for her clients in a wide variety of high-stakes litigation, intellectual property matters, and complex commercial disputes. Ms. Plessman has developed creative and practical strategies for clients across a diverse set of industries, from asset management to technology to entertainment. She has served as lead counsel in multibillion-dollar wildland fire litigation, secured victories on behalf of clients seeking to enforce their contractual and intellectual property rights, and obtained dismissals on behalf of clients wrongfully accused of misconduct. Her practice includes class and derivative actions, mass tort and securities litigation, and other civil litigation arising from intellectual property, contract, fiduciary duty, employment, defamation, and professional negligence disputes.

Ms. Plessman has also successfully defended companies, boards of directors, and individuals facing regulatory investigations and criminal enforcement actions, securing pre- and post-indictment dismissals. She also regularly advises clients on their most sensitive and confidential internal matters, including on matters relating to corporate governance, regulatory compliance, whistleblowing, discrimination, breaches of fiduciary duty, trade secrets misappropriation, termination, and unfair competition.

Ms. Plessman began her legal career as a litigation associate at Wachtell, Lipton, Rosen & Katz in New York City before joining Irell & Manella, where she was elected partner.

During law school, Ms. Plessman was named a Harlan Fiske Stone Scholar and won the Frederick H. Weisberg Award in Constitutional Law. As an undergraduate, she graduated summa cum laude and was a member of Phi Beta Kappa and Phi Kappa Phi.

Updated Oct 2025

  • Ms. Plessman led the team that secured dismissal of a defamation action seeking tens of millions of dollars against TCW, a leading global asset management firm. She also defeated a FINRA action brought against TCW, which the petitioner agreed to withdraw with prejudice following aggressive responsive filings made on behalf of TCW. She is currently representing TCW in an action it filed against a former officer seeking tens of millions of dollars in damages and disgorgement, which alleges multiple breaches of fiduciary duties, including sexual harassment of subordinates. The court recently denied the former officer’s motion to dismiss TCW’s faithless servant claim, among others, which has important implications for the application of the faithless servant doctrine in the sexual harassment context.

  • Ms. Plessman is defending a Western utility in multiple lawsuits filed in jurisdictions across Oregon and California arising out of the 2020 Labor Day Fires. The fires burned over 500,000 acres across at least five counties in Oregon and California and allegedly destroyed over 2,000 structures. Her role includes defense of all civil litigation, including serving as lead counsel in numerous jury trials, and consultation and engagement with regulatory and investigatory agencies.

  • Ms. Plessman is representing Broadcom and its affiliates as lead counsel in numerous intellectual property matters, including copyright infringement lawsuits currently pending against Delta, Allstate, and Kenvue Brands/Johnson & Johnson, as well as contract matters against T-Mobile, DST, Credit Suisse, and General Motors. She previously secured the dismissal of a lawsuit against Broadcom brought by TomTom International, B.V. alleging breach of warranty, and has secured numerous favorable settlements for Broadcom over the years.

  • Ms. Plessman is currently representing OpenAI in litigation against Elon Musk. Musk alleges, among other things, that OpenAI breached its non-profit mission. The case is scheduled for trial in 2026.

  • Ms. Plessman secured a series of trial court and appellate wins and ultimately a settlement on behalf of shareholders of SweeGen, Inc. in a derivative lawsuit alleging breaches of fiduciary duties, self-dealing, securities fraud, conversion, and conspiracy. She obtained a preliminary injunction on behalf of the shareholders at the outset of the litigation and persuaded the California Court of Appeal to uphold the injunction.

  • Class action
  • Commercial disputes
  • Competition/antitrust
  • Environmental
  • Intellectual Property
  • Product liability and recall
  • Securities
  • White collar crime

  • Accounting
  • Banking
  • Consumer goods and services
  • Energy
  • Food and beverage
  • Gaming
  • Healthcare
  • Investment management
  • Pharmaceutical and life sciences
  • Technology and telecommunications
  • Utilities

  • Columbia Law School (J.D., 2003)
  • University of Minnesota (B.A., 1999, Political Science) summa cum laude 

  • Board of Directors, Western Center on Law & Poverty (co-chair of Nominating Committee)
  • Member, Women’s White Collar Defense Association 

  • California 
  • New York