Mr. Posner is a partner in the Los Angeles office of Quinn Emanuel. He is the Co-Chair of the firm’s Trademark and Copyright Practice Group and a leader of the firm’s California appellate practice. His diverse practice focuses on complex litigation at the trial court and appellate levels on behalf of plaintiffs and defendants, particularly involving intellectual-property disputes, commercial disputes, employment discrimination, and products liability.
Among his extensive experience in intellectual-property matters, Mr. Posner has successfully represented clients in trials and appeals touching on a variety of matters within the entertainment, technology, consumer products, and fashion industries. He has helped his clients protect some of the most famous and valuable brands in existence by pursuing and defending against claims of unauthorized use in federal courts and in the U.S. Patent and Trademark Office. Mr. Posner also has had substantial success representing foreign clients in IP litigation in U.S. courts, with a particular focus on representing clients from Asian countries both to protect their IP rights and defend them against claims of infringement.
Mr. Posner has prevailed in several trials, including jury trials and arbitration proceedings, and has helped his clients (plaintiffs and defendants) recover their attorney’s fees after prevailing at trial on multiple occasions. Mr. Posner also has been asked on several occasions to take over existing matters for purposes of discovery or trial after a client has obtained unfavorable pre-trial rulings, or for purposes of appeal after a client has obtained an unfavorable judgment after trial.
Mr. Posner has been recognized by the World Trademark Review 1000 as a Recommended Individual who is "renowned for his courtroom prowess and tenacity” and “flourishes on both sides of the ‘v’, securing victories in diverse industries.”
Before joining the firm, Mr. Posner clerked for the former Chief Judge of the Central District of California, the Honorable George H. King (ret.).
- Tesla
- X Corp. (formerly Twitter, Inc.)
- Samsara Inc.
- VIZIO
- Academy of Motion Picture Arts & Sciences
- Playboy Enterprises International
- Zuru, Inc.
- Mattel
- Snail Games USA
- Zazzle, Inc.
- IWG/Regus
- Primer Technologies, Inc.
- Tsuburaya Productions
- teamLab
- Pharrell Williams & Robin Thicke
- IAC/InteractiveCorp
- After being retained by Tesla to challenge a $137 million jury verdict against Tesla that represented the largest single-plaintiff verdict in an employment discrimination case in U.S. history, Mr. Posner helped obtain a new damages trial for Tesla. After a week-long trial in which the second jury was instructed that it must award some amount of compensatory and punitive damages, the jury returned a verdict totaling $3.175 million, representing a reduction of almost 98% in the amount the first jury awarded. Mr. Posner spoke with firm founder John B. Quinn about the result on Mr. Quinn’s podcast, available here: https://open.spotify.com/episode/2pGshsKMY7tNsPDtGDLZxp?si=11f47c9036a64bbb.
- For artificial-intelligence company Primer Technologies, Inc. and its CEO and Founder, Mr. Posner defeated claims of trade-secret misappropriation and breach of contract brought by Quid, Inc., that Quid alleged were worth more than $150 million. After a week-long “zoom” arbitration hearing in July 2020 (which was one of the first of its kind), Mr. Posner’s client was declared the “prevailing party” and awarded more than $6 million in attorney’s fees and costs.
- For Japanese entertainment company Tsuburaya Productions, Mr. Posner obtained two significant victories on summary judgment followed by a complete victory following a two-week jury trial in the Central District of California in a copyright infringement case involving rights in the iconic “Ultraman” superhero character created by Tsuburaya in the 1960’s. The district court awarded Tsuburaya its attorney’s fees as the “prevailing party” under the Copyright Act. The judgment in Tsuburaya’s favor was subsequently affirmed by the Ninth Circuit Court of Appeals. (See Mr. Posner’s appellate argument here: https://www.ca9.uscourts.gov/media/view_video.php?pk_vid=0000016592.)
- Mr. Posner is representing toy company Zuru against Lego in multiple matters in federal district court and the USPTO involving copyright and trademark claims relating to Lego’s asserted intellectual-property rights in its “minifigure” product and in the word “lego.”
- Mr. Posner is representing X Corp. (formerly Twitter, Inc.) in copyright infringement matters asserting that X Corp. failed to expeditiously remove alleged copyrighted content posted by X Corp. users and did not suspend the accounts of alleged repeat infringers. These cases raise novel and important questions about the rights and obligations of an Internet service provider under the Digital Millennium Copyright Act relating to content posted by users, and the obligations of a copyright owner to provide adequate notice of such alleged acts of infringement.
- In a commercial real estate dispute for Samsara involving a high-profile property in San Francisco, Mr. Posner obtained the reversal of an order of attachment against Samsara in the California Court of Appeal. (See RREEF America REIT v. Samsara Inc., 91 Cal.App.5th 609 (May 15, 2023).) In a matter of significant importance for the Academy of Motion Picture Arts & Sciences, Mr. Posner obtained affirmance of a judgment reinforcing the Academy’s rights in the iconic “Oscar” statuette. (See Juarez v. Ward, 88 Cal.App.5th 730 (Feb. 24, 2023).)
- For Mattel in its long-running litigation against competitor MGA Entertainment, Mr. Posner obtained an order from the Ninth Circuit vacating verdicts of liability for alleged trade-secret misappropriation and a damages award of more than $170 million; separately defeated antitrust and RICO claims purportedly worth $3 billion and RICO claims with similar alleged stakes; and obtained summary judgment on trade-secrets claims allegedly worth $1 billion in an order that was affirmed by the California Court of Appeal and Supreme Court.
- Following on Mr. Posner’s successful representation of Gucci America in claims involving its iconic “green-red-green” and “blue-red-blue” trademark rights, Mr. Posner assisted Playboy Enterprises International in protecting its famous trademark rights against unauthorized uses in the fashion industry.
- Mr. Posner represented Samsung in patent and trade-dress matters involving smartphone and tablet computers, including in proceedings in the district court and the Federal Circuit Court of Appeals.
- Appellate Practice
- Artificial Intelligence
- Class Action Litigation
- Copyright Litigation
- Internet Litigation
- Litigation Representing Plaintiffs
- Entertainment & Media Litigation
- Trade Secret Litigation
- Trademark, Trade Dress, Unfair Competition/False Advertising, and Publicity Rights Litigation
- Cannabis Litigation
- Employment Litigation & Counseling
- Commercial Litigation
- Georgetown University Law Center
(J.D., cum laude, 2003)
American Criminal Law Review, Editor
Global Law Scholar
Law Fellow - University of California at Berkeley
(B.A., Development Studies, with honors, 1998)
- The State Bar of California
- United States Court of Appeals:
- Third Circuit
- Ninth Circuit
- Tenth Circuit
- Eleventh Circuit
- United States District Courts:
- Central District of California
- Eastern District of California
- Judicial Clerk for the Honorable George H. King:
- United States District Court for the Central District of California, 2003-2004
- Named a “Recommended Individual” by the World Trademark Review 1000, 2025
- Ranked by Legal 500 USA, Intellectual Property: Copyright, “Recommended Lawyers,” 2023 and 2024
- Ranked by Legal 500 USA, Intellectual Property: Trademarks: Litigation, “Recommended Lawyers,” 2023 and 2024
- Ranked by Legal 500 USA, Media, Technology, and Telecoms: Media and Entertainment: Litigation, “Recommended Lawyers,” 2024
- Ranked by The Best Lawyers in America, Litigation - Intellectual Property, 2024
