Stefan Mentzer

Stefan Mentzer

Spoken Languages
English German
Stefan Mentzer
New York
+1 212 459 7088

Stefan Mentzer, a partner in Goodwin’s IP litigation practice, has represented clients in high-stakes, precedent-setting matters for more than two decades. Stefan advocates for clients in a wide range of commercial and intellectual property disputes, and across an array of industries, including for consumer electronics, online platform, ecommerce, media, music, medical device, pharmaceutical, automotive, manufacturing, and financial services companies.

Among his work, Stefan successfully defended against copyright infringement claims involving renowned visual artist Jeff Koons, establishing a leading precedent on fair use (Blanch v. Koons). On behalf of one of the world’s largest stainless steel manufacturers, Stefan helped secure a total win against a competitor in a complex cross-border trade secret case. Stefan obtained a rare Alice step 2 reversal from the Federal Circuit for a Germany-based developer of multifactor authentication technology, which Law360 recognized as one of the “Biggest Patent Rulings of 2021.”

Stefan’s areas of focus include copyright, trade secrets, trademark, unfair competition, complex commercial disputes, and music licensing. Stefan has extensive experience in bench and jury trials and appeals, both state and federal, and he has practiced in proceedings before the International Trade Commission, the U.S. Copyright Office, and the U.S. Patent and Trademark Office.

BTI Consulting Group has named Stefan Mentzer among its “Client Service All-Star Attorneys” in a survey of top legal decision-makers at large organizations with $1 billion or more in revenue. The Financial Times “highly commended” Stefan’s stainless steel trade secret win (FT Innovative Lawyers North America), and WTR 1000 repeatedly has recognized Stefan among its “Recommended Individuals.” Stefan has received accolades for his legal writing, including a Burton Award for Distinguished Legal Writing, a first prize in the Nathan Burkan Memorial Competition for writing in the field of copyright law, and recognition by The National Law Journal for a “brief of the week” submitted to the U.S. Supreme Court.


Trade Secret Litigation

  • Valbruna. Successfully represented a leading stainless steel manufacturer in a Section 337 proceeding before the U.S. International Trade Commission. The ITC found that the respondent, an India-based stainless steel producer, misappropriated the client’s trade secrets, and it issued orders prohibiting the respondent’s importation and sale of stainless steel products for more than 16 years. Stefan argued the appeal to the Federal Circuit, which affirmed the Commission’s determination, resulting in a complete victory for the client.*
  • Pfizer. Represented Pfizer in litigation against Merck concerning alleged misappropriation of trade secrets and confidential business information in the development of multi-conjugate pneumococcal vaccines.*

Copyright Litigation

  • Blanch v. Koons. Successfully defended Deutsche Bank against claims by a freelance photographer who alleged infringement by visual artist Jeff Koons. Obtained a total win in the Southern District of New York and at the Second Circuit Court of Appeals, establishing a leading precedent on copyright fair use.*
  • Pfizer. Lead counsel for pharmaceutical company in a copyright infringement lawsuit alleging infringement of a song used in television advertising campaign for Advil.*
  • Lemonade. Successfully represented insurtech leader in copyright infringement litigation against copycat producers of property and casualty insurance app, located in Germany, Switzerland, and Liechtenstein.*
  • iFIT. Retained as a copyright law and music licensing expert on behalf of iFIT, a leading health and fitness platform, in litigation against Peloton.*
  • Museums of Art. Counsel of record for 28 museums of art, including the Solomon R. Guggenheim Foundation, the Art Institute of Chicago, and the Whitney Museum of American Art, in Kirtsaeng v. John Wiley & Sons. The U.S. Supreme Court relied on the museum amici’s arguments as support for its landmark decision that the “first sale” doctrine applies to foreign-manufactured goods, and The National Law Journal featured the museum brief as its “brief of the week.”*

Technology, Medical Device, and Pharmaceutical Patent Litigation

  • CosmoKey Solutions. Representing Germany-based developer of security and authentication technology in patent infringement litigation against Duo Security, a subsidiary of Cisco. Prevailed against Duo in a motion to dismiss for failure to state a claim and in two inter partes review proceedings. Obtained a rare reversal from the Federal Circuit under Alice step 2, in which the court ruled that the client’s patent recites a specific improvement to a particular computer-implemented authentication technique.*
  • Abiomed. Represented Abiomed in a patent infringement dispute regarding the company’s core product, the Impella® line of heart pumps. After a favorable Markman ruling, the Court granted summary judgment of non-infringement, giving Abiomed a complete victory and clearing the way for the company’s $16.6 billion acquisition by Johnson & Johnson.*
  • Biotronik. Represented Biotronik, a cardiovascular biomedical research and technology company, in patent infringement litigations involving coronary stent technology. Successfully challenged jurisdiction and venue claimed by the plaintiff, resulting in plaintiff withdrawing its Western District of Texas action and allowing the parties to proceed in our client’s preferred venue.*
  • Samsung Bioepis. Represented Samsung Bioepis in a Section 1782 proceeding against a competitor that sought broad discovery for use in patent litigations worldwide. After extensive motion practice involving the novel issue of whether the Biologics Price Competition and Innovation Act (BPCIA) bars such discovery, the competitor withdrew its application, a significant win for the client.*

Trademark and Unfair Competition Litigation

  • Walmart. Represented Walmart in trademark and trade dress disputes involving the company’s e-commerce platform. Defended Walmart against trade dress and design patent claims brought by the manufacturer of Ugg footwear, and in a lawsuit brought by a manufacturer of stationary exercise bicycles alleging trademark infringement and unfair competition for use of the terms “spin” and “spinning.”*
  • Abiomed. Defeated opponent’s motion to amend complaint to add false advertising claims under the Lanham Act and state law, persuading the court that the purported false advertising claims arose from entirely different transactions and facts – a crucial win for the client.*
  • Mahindra & Mahindra. Represented India-based vehicle manufacturer in appeal of ITC’s Section 337 trade dress infringement determinations. The Federal Circuit ruled that Mahindra’s redesigned vehicle did not infringe the claimant’s claimed trade dress in “jeep” vehicles, giving the client a significant win and allowing it to continue importing its products into the U.S.*
  • International Wildlife Coexistence Network. Defended wildlife preservation non-profit, which advocates for the relisting of gray wolves on the federal endangered species list, against a plaintiff that claimed to own trademark rights in the term #RelistWolves. Won dismissal in Montana of plaintiff’s complaint on personal jurisdiction grounds and denial in Idaho of plaintiff’s motion for a preliminary injunction.*

Music Litigation and Counseling

  • Music Royalty Rate-Setting and Distribution Proceedings. Represented a leading performing rights licensing organization in federal court cases to determine reasonable fees for the public performance of copyrighted musical works by internet and commercial music services, and in U.S. Copyright Office proceedings for the distribution of cable retransmission royalties.*
  • Square Acquisition of TIDAL. Advised Square on music IP and licensing issues in the company’s acquisition of a majority ownership stake in TIDAL, the global music and entertainment platform.*
  • LINE Acquisition of MixRadio. Advised LINE on all aspects of music IP and licensing issues in LINE’s acquisition of music streaming service MixRadio from Microsoft.*

Complex Civil Litigation

  • Average Wholesale Price Pharmaceutical Litigation. Represented a leading pharmaceutical manufacturer in a false claims act, common law fraud, and consumer protection lawsuits brought by state attorneys general and a qui tam realtor for the reporting of Average Wholesale Price (AWP) and Wholesale Acquisition Cost (WAC) data used in Medicaid reimbursements. Helped win reversal of a $78 million verdict in Sandoz Inc. v. Alabama and a $28 million judgment in Sandoz Inc. v. Kentucky.*

*Denotes experience prior to joining Goodwin.

Professional Activities

Stefan previously served as Chair of the Copyright Law Committee of the American Intellectual Property Law Association (AIPLA), a 15,000-member national bar association.

Professional Experience

Prior to joining Goodwin, Stefan was a partner at White & Case.




Georgetown University Law Center

(cum laude)


Yale University

(cum laude)



  • New York


  • U.S. District Court for the Eastern District of New York
  • U.S. District Court for the Southern District of New York
  • U.S. District Court for the District of New Mexico
  • U.S. District Court for the Eastern District of Wisconsin
  • U.S. Court of Appeals for the Federal Circuit
  • U.S. Court of Appeals for the Second Circuit
  • U.S. Supreme Court

Recognition & Awards

  • Recommended Lawyer (Patent Litigation: Full Coverage and Trade Secrets), Legal 500 US, 2024
  • Client Service All-Star 2018, BTI Consulting
  • New York Super Lawyers, 2013-2023
  • Rising Star, New York Super Lawyers, 2011, 2012
  • Leading Trademark Professional, WTR 1000, 2021-2023
  • Burton Award, Distinguished Legal Writing, 2015
  • First Prize, Nathan Burkan Memorial Competition, 2001



  • “Website Terms of Service – Enforceable or Preempted?” The Licensing Journal, November/December 2022 (co-author)
  • “Joinder and Early Discovery in Bittorrent Copyright Infringement Lawsuits,” Cardozo Arts & Entertainment Law Journal, 2015 (co-author)
  • “9th Circ. Made 3 Errors In ‘Innocence Of Muslims’ Ruling,” Law360, March 19, 2014 (co-author)
  • “The Fifth Amendment Versus Compelled Production of Encrypted Data,” ABA Section of Litigation Pretrial Practice & Discovery, November 15, 2012 (co-author)
  • “What You Need to Know Before You File a Copyright Infringement Lawsuit,” Intellectual Property & Technology Law Journal, March 2012

Speaking Engagements

  • “Royalty-Free Patents and Open Standards in Open Source Software,” November 13, 2019: The Practising Law Institute, The Law and Business of Open Source Software (speaker)
  • “Multi-Jurisdictional Issues in Global IP Management,” September 26, 2017: Corporate Counsel’s 29th Annual General Counsel Conference (moderator)
  • “Smart Devices Are Reconfiguring Our World,” September 21, 2017: White & Case Back-to-Business Japan Seminar Series (panelist)
  • “Cranes, Trains, and Digital Goods: Trade Secret and Copyright Developments at the International Trade Commission,” January 28, 2016: AIPLA Mid-Winter Institute (speaker)
  • “Coming to an Auction House Near You? The Revived Debate Over Art Resale Royalties,” January 15, 2015: Copyright Society of the U.S.A. (speaker)
  • “What Entrepreneurs Need to Know about Intellectual Property,” March 4, 2014: Cardozo Annual Intellectual Property Law Forum (panelist)
  • “Patent Prosecution and Copyright Protections Collide – Use of Non-Patent Literature During Patent Examination,” May 1, 2013: AIPLA Spring Meeting (speaker)
  • “History and Purposes of Formalities,” April 18, 2013: Berkeley Center for Law and Technology Symposium, Reform(aliz)ing Copyright for the Internet Age (moderator)
  • “Is Copyright Infringement a Necessary Step for Patent Prosecution?” December 12, 2012: ABA Intellectual Property Roundtable (moderator)
  • “Copyright Issues in the Law Library Environment,” June 3, 2010, June 9, 2011, June 7, 2012: St. John’s University (guest lecturer)
  • “Copyright Claims for Disclosing Non-Patent Literature to the USPTO,” May 11, 2012: AIPLA Spring Meeting (speaker)
  • “Who Is Concerned about Broader Access to Orphan Works and Why,” April 12, 2012: Berkeley Center For Law and Technology Symposium on Orphan Works and Mass Digitization (moderator)
  • “Copyright Lawsuits from the Get Go: Initial Challenges for Registrants, Plaintiffs, and Defendants,” October 21, 2011: AIPLA Annual Meeting (speaker)


Stefan has been quoted by Corporate Counsel, The National Law Journal, The New York Law Journal, The New York Observer, The Washington Post, Fortune, Wired, Law360, Reuters, and The Associated Press.