Dimitri Portnoi

O'Melveny & Myers LLP

Dimitri D. Portnoi is an experienced litigator who represents clients in a wide range of complex business litigation, financial service, and entertainment matters, including consumer class actions, unfair competition, business torts, fraud, contract and related commercial litigation.

Dimitri has represented clients in a diverse array of industries, including entertainment, health care, natural resources, finance and banking, communications, and manufacturing. These clients have worked with Dimitri in a variety of matters, including federal constitutional cases, international law and the Alien Tort Statute, copyright and trademark law, products liability, federal anti-discrimination law, state tax litigation, consumer class actions, ERISA litigation, and contract and related commercial litigation.

As a core member of the Firm’s Water industry group, Dimitri’s clients also rely on his expertise in water law and regulatory law, and call on him frequently for counsel on both litigation matters and transactions. Dimitri has worked on multiple trials, both as trial and appellate counsel, and on numerous appeals.


  • Representing medical-device manufacturers as appellate counsel in complex and ongoing products liability litigation.
  • Securing the dismissal of Fair Housing Act lawsuits brought by municipal entities against a leading global bank.
  • Representing a financial services company in Attorney General lawsuits asserting violations of consumer protection laws, bringing a motion to dismiss in federal district court and litigating two appeals in the Ninth Circuit concerning the scope of the Class Action Fairness Act (CAFA).
  • Representing a major health services company in a class action lawsuit alleging improper reimbursement procedures and implicating significant issues of preemption under the Employment Retirement Income Security Act (ERISA).
  • Counseling a nationwide trade association concerning the federal constitutional implications of several municipalities’ proposals to exercise eminent domain authority over underwater mortgages.
  • Representing a major motion picture studio in a contract, intellectual property, and First Amendment dispute involving several successful appeals before the Ninth Circuit and extensive motion practice before the district court.
  • Defending a major energy company against a suit arising under the Alien Tort Statute, resulting in a quick and decisive victory before the district court.
  • Representing major pharmaceutical manufacturers against Medicaid reimbursement, fraud and unfair trade practices claims brought by numerous State Attorneys General in petitions to respective state supreme courts.
  • Counseling a land developer on potential challenges under California’s administrative and environmental laws to a municipality’s indefinite delay of a significant residential development project.
  • Successfully representing a group of Nevada couples seeking to overturn that State’s ban on same-sex marriage.
  • Representing before the Ninth Circuit a California prisoner in a Section 1983 challenge to his designation as a gang associate that resulted in his indefinite assignment to solitary confinement.


  • California


  • New York University, J.D.: magna cum laude: Order of the Coif; Senior Articles Editor of New York University Law Review; Fellow, Center for Research in Crime and Justice; Pomeroy Scholar (top ten students in first-year class); Allen Scholar (top ten percent of students at end of second year; Paul D. Kaufman Law Review Prize (faculty-decided award for most outstanding student note)
  • Columbia University, B.A., Political Science


Rate : $$$

What types of cases Attorney Dimitri Portnoi & O'Melveny & Myers LLP can handle?
O'Melveny & Myers LLP can handle cases related to laws concerning Financial Services, Litigation, Entertainment, Consumer Rights & Protection, Class Action, Health Care. We manually verify each attorney’s practice areas before approving their profiles and reviews on our website.
Where is O'Melveny & Myers LLP located?
O'Melveny & Myers LLP is located at 400 S Hope St #18th+floor, Los Angeles, CA 90071, USA. You can reach out to O'Melveny & Myers LLP using their phone line 213-430-7699. You can also check their website omm.com or email them at [email protected].
How much would it cost to hire O'Melveny & Myers LLP?
Dimitri Portnoi lawyer charges are specific to each case. However, they work with contingency fees and its ranges from $$ to $$$. They also provide free consultation [and no obligation quotes] if you are interested to hire.
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O'Melveny & Myers LLP
400 S Hope St #18th+floor, Los Angeles, CA 90071, USA
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