Alison L. Plessman

“This securities litigator wins big, particularly when her clients are the biggest on earth.
—“Lawyers on the Fast Track,” The Recorder

Alison L. Plessman consistently delivers successful outcomes for high-profile clients faced with complex, challenging business, regulatory, and criminal matters. She represents both plaintiffs and defendants in high-stakes commercial litigation matters in several areas, including securities, health care and insurance fraud, trade secret misappropriation, RICO violations, accounting irregularities and market manipulation, professional negligence, and breaches of contract and fiduciary duties. She also has successfully defended companies, boards of directors, and individuals facing regulatory investigations and criminal enforcement actions, securing many pre- and post-indictment dismissals.

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 was a member of Phi Beta Kappa and Phi Kappa Phi.

Representative Experience

  • Representing Southern California Edison and Edison International in litigation arising out of the 2017 Thomas Fire and 2018 Montecito mudslides.
  • Represented Western Digital and its SanDisk subsidiaries in their widely publicized dispute with Toshiba over anti-transfer provisions in joint venture agreements governing the manufacture and development of NAND flash memory. The dispute encompasses multiple ICC arbitrations and litigation in the California trial and appellate courts, where SanDisk secured injunctive relief in aid of the arbitrations.
  • Represent Hong Kong investment company in multiparty RICO action alleging violations of U.S. export control laws.
  • Defended a leading global professional services company against an $830 million actuarial malpractice lawsuit brought by the city of Houston in connection with the city’s $6.2 billion pension crisis and obtained a favorable settlement.
  • Served as trial counsel for T-Mobile in a successful trade secrets lawsuit against the Chinese smartphone maker Huawei Technologies alleging the manufacturer stole T-Mobile’s smartphone testing robot.
  • Successfully defended investment bank professional in U.S. Treasuries probe conducted by the SEC and the Commodities Future Trading Commission, resulting in no charges or fines.

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  • Successfully defended senior executive at a global investment firm in a multiyear investigation being conducted by the SEC, resulting in no charges or fines.
  • Defended senior executive at international gaming company in whistleblower suit investigated by the SEC, resulting in no charges or fines.
  • Represented Glaukos against a claim of inequitable conduct in a complex patent matter in Delaware federal court. The case was settled three days before trial on favorable terms for our client.
  • Won dismissal of criminal mortgage fraud indictment after evidentiary hearings for prosecutorial misconduct. (See “Judge Dismisses Case Against Oil Heir Hill, Finds Dallas DA in Contempt,” The Dallas Morning News)
  • Obtained $20 million for Pacific Life against Bank of New York Mellon at the summary judgment stage in a breach of contract and breach of fiduciary duty matter in investment mismanagement litigation, later obtaining an additional $30 million for Pacific Life in a settlement on the eve of trial.
  • Represented Universal Music Group in a nine-figure negligence and breach of contract lawsuit concerning media assets that were destroyed in a fire at NBC Universal’s studio lot. Reached a favorable settlement shortly before the start of trial and after successfully adding a punitive damages claim.
  • Served on the winning trial team in the $2.2 billion insurance dispute between Silverstein Properties and several insurance companies concerning the collapse of the World Trade Center in the aftermath of the September 11 attacks.
  • Successfully defended Kenneth Langone’s Invemed Associates in a disciplinary proceeding before the National Association of Securities Dealers (NASD, now FINRA) that resulted in what The New York Times called a “withering,” “high-profile defeat” for the regulators.
  • Represented the New York Stock Exchange (NYSE) in litigation with dissident seatholders following the announcement of the NYSE’s historic merger with Archipelago. During the preliminary injunction hearing, the parties reached a settlement that allowed the vote on the merger to proceed as scheduled.
Alison Plessman

Alison L. Plessman

Partner 213.788.4542 Download vcard


Columbia Law School (J.D., 2003)

University of Minnesota (B.A., Political Science, 1999) summa cum laude