Sullivan & Cromwell LLP Logo
  • Home
  • Lawyers
  • Practices
  • Insights
  • About
  • Careers
  • Alumni
  • Twitter icon
  • LinkedIn icon
  •  icon
  • Podcasts icon
© 2025 Sullivan & Cromwell LLP
    • Home
    • Lawyers
    • Practices
    • Insights
    • About
    • Careers
    • Alumni
    Home /  Lawyers /  Marc De Leeuw

    Marc De Leeuw

    Partner

    Marc De Leeuw Headshot Photo Portrait backdrop

    New York

    +1-212-558-4219

    |

    deleeuwm@sullcrom.com

    Email vCard

    Marc De Leeuw has been a partner at Sullivan & Cromwell since 2001. His litigation practice includes representing clients in a variety of areas, including intellectual property, securities, antitrust, real estate, contract, bankruptcy, and many other commercial matters.

    Marc has represented clients before arbitration tribunals, the International Trade Commission, New York and New Jersey state trial and appellate courts, numerous federal district courts and Courts of Appeals and the U.S. Supreme Court. He has represented clients in trials and arbitration hearings in intellectual property, antitrust, tort, contract and insurance cases.

    Marc has been recognized many times as a New York Super Lawyer and as a “Future Star” by Benchmark Litigation. He has been named multiple times in the AmLaw “Litigator of the Week,” and by the National Law Journal for his successful representation of Microsoft in a major antitrust jury trial.

    Professional Activities and Community Involvement

    • Co-author of “Declaratory Judgments” chapter in Commercial Litigation in New York State Courts
    • Serves as Chair of the Board of Directors of Mobilization for Justice
    • Represented pro bono the St. Andrew’s Society of the State of New York
    • Served on the New York City Bar Association Judiciary Committee
    • PLI Panel Member, “Handling a Securities Case: From Investigation to Trial and Everything in Between” (2012, 2013)
    • Author of “Recent Patent Decisions and How They Affect Patent Law,” in Developing a Patent Strategy (2010)
    • Speaker at professional conferences concerning cross-border class actions and investment company and patent litigation
    Read More

    Spotlight

    S&C’s Garrard Beeney, Marc De Leeuw and Dustin Guzior Named ‘Litigators of the Week’ for Ocado Settlement in ‘Robot Wars’

    Read More

    In Global IP Disputes Called the ‘Robot Wars,’ S&C Secures Settlement for Client Ocado Group plc

    Read More
    ocado_billboard_v4

    Marc de Leeuw recognized as a “Future Star” by Benchmark

    Read More
    • Experience
    • Rankings and Recognitions
    • News
    • Publications, Videos and Podcasts
    • Credentials
    • Related Practices
    Experience

    Experience

    Intellectual Property

    • Ocado in multiple cases against AutoStore relating to patents on robots and cubic auto storage and retrieval systems, including a complete victory in ITC trial
    • AB InBev and Modelo in trademark infringement and contract actions involving sales of Corona Hard Seltzer and Patagonia beer
    • Fifteen major universities in a joint patent licensing program called University Technology Licensing Program

    • Novo Nordisk in a variety of patent and false advertising matters, including in patent infringement actions, an ITC investigation involving patents on hemophilia drugs, an arbitration involving royalties on diabetes products, and a false advertising action involving advertisements for diabetes drugs
    • Audio MPEG, Philips, TDF, and IRT in a patent infringement action against Dell involving patents on MP-3 technology
    • Philips Electronics in multiple patent infringement actions, including obtaining a substantial verdict at trial with an award of attorneys’ fees, and in successful appeal concerning infringement of Philips’ patents on universal remote control technology and in worldwide litigation involving Philips’ patents on cellular, CD, and DVD technology
    • MobileMedia Ideas in patent infringement actions against Apple, RIM, and HTC involving multiple patents on smartphone technology
    • General Electric, LG Electronics, Mitsubishi Electric, Samsung, BT, Thomson Licensing, Columbia University, Philips, JVC, and Sony in actions against Lenovo and Haier for infringing patents essential to the MPEG-2 and ATSC digital video compression and transmission standards
    • VeriFone in actions involving its patent on payment terminal security, false advertising claims, and contract and tort claims, including obtaining the denial of a preliminary injunction of VeriFone’s advertising of free service for competitors’ customers
    • Dyson in patent and false advertising litigation concerning the design and capabilities of its vacuum cleaners, including obtaining summary judgment in two actions dismissing plaintiffs’ patent claims against Dyson
    • Labatt in a patent infringement action, including at trial, involving its patent on a method for brewing “ice” beer
    • Fonar, a manufacturer of MRI scanners, in a successful appeal to the U.S. Court of Appeals for the Second Circuit seeking to protect Fonar’s copyright on its maintenance software

    Securities

    • Abiomed in securing dismissal of all claims in a putative securities class action filed in the Southern District of New York
    • Ally Financial (formerly GMAC) in a securities class action based on disclosures about Ally’s subprime auto loan business, including obtaining dismissal of the action in Michigan state court for failure to plead an actionable false or misleading statement
    • BP in multiple securities, shareholder derivative, and ERISA class actions arising out of the Gulf of Mexico and Prudhoe Bay oil spills, including in obtaining dismissal of the federal shareholder derivative action on the ground of forum non conveniens and dismissal of a class action challenging the cancellation of a BP quarterly dividend
    • Banco Bradesco in a securities class action relating to Brazil’s “Operation Zelotes” tax corruption investigation
    • Barclays in nationwide Enron litigation, including a securities class action and related proceedings and obtaining reversal of the district court’s decision to certify a class of Enron shareholders to pursue securities claims against Barclays and others seeking $40 billion in damages
    • Cablevision in shareholder derivative and class actions concerning options “backdating” and “going private” offers
    • Various mutual funds and their directors in investigations and civil actions concerning board decisions and fund practices

    Antitrust

    • Ally Financial in multiple antitrust class actions relating to trading of GameStop and other stocks in so-called “short squeeze” purchases
    • Novo Nordisk in an antitrust class action alleging Novo sought to exclude generic competition for its Prandin® diabetes drug
    • Microsoft in a variety of private antitrust and related matters, including at a preliminary injunction hearing and seven-week trial in successfully defending against an antitrust action brought by Bristol Technology; in an antitrust and copyright action brought by Sun Microsystems, including through a preliminary injunction hearing and appeal; and in an antitrust action brought by Netscape Communications
    • Fonar at trial in a successful defense of antitrust claims alleging monopolization of an alleged market for service of Fonar MRI scanners

    Other Commercial Matters

    • Barclays in a suit brought by a hedge fund arising out of termination of a $1 billion total return swap transaction, including a complete trial victory after which the New York Supreme Court held that Barclays had no liability to the hedge fund, and the appeal, in which the Appellate Division, First Department, unanimously affirmed that trial victory
    • New York Football Giants and New York Jets in litigation against the New Jersey Sports & Exposition Authority and developers of the proposed “American Dream” mall in New Jersey seeking to prevent construction of that mall
    • Foxconn (Hon Hai Technology Group) and Belkin in a dispute with Fortinet and Linksys arising out of Foxconn’s ownership of Belkin and Linksys and Belkin services provided to Linksys
    • Prada in litigation involving its long-term lease for its flagship Fifth Avenue store
    • Eisai in a breach of contract action against Pfizer and Viatris relating to sales of the generic form of Lyrica® in Japan
    • Vornado Realty Trust in actions brought by Donald Trump relating to the sale of the “Riverside South” properties on the West Side of Manhattan that Trump claimed undervalued the properties by more than $1 billion, and in actions relating to properties including those at the Georgetown Park Mall, Times Square, Union Square South, Penn Plaza, and Harlem Park
    • Canary Wharf in pursuing a $780 million claim in the Lehman bankruptcy
    • J.C. Flowers & Co. in a breach-of-contract action brought by investment funds after Flowers terminated a stock purchase agreement for the sale of a controlling interest in an insurance company, including obtaining, on appeal to the Appellate Division of the New York State Supreme Court, First Division, reversal of plaintiffs’ $17 million summary judgment award and dismissal of the complaint in its entirety
    • Oxford Health Plans (now part of UnitedHealth Group) in a variety of matters related to health insurance and reinsurance, including in arbitrations over rescission claims made by reinsurers and in a variety of private and class actions and “class arbitrations” brought by physicians and medical societies concerning Oxford’s reimbursement policies and practices
    • The Bank of New York in investigations and civil actions concerning the Bank’s business with certain Russian customers
    • Softbank in connection with contract, tort and fiduciary duty claims brought by a video game development company in which Softbank invested
    Read More
    Rankings and Recognitions

    Rankings and Recognitions

    • Concurrences Review – Best Antitrust Business Article: Intellectual Property Category (2020)
    • New York Super Lawyers (2010, 2013–2022)
    • AmLaw Litigation Daily – “Litigator of the Week” (July 2023; runner-up in December 2018, January 2019, October 2019)
    • The Legal 500 United States (2015)
    • Benchmark Litigation – Future Star (2020–2023) and Litigation Star (2024–2025) 
    • National Law Journal – Bristol v. Microsoft named one of the “major civil-suit verdicts that beat the odds” (May 2000)
    Read More
    News

    News

    • S&C Prevails at Class Certification for Rock Holdings in Securities Fraud and Insider Trading Action

      October 11, 2024
    • S&C Prevails for Barclays in Dispute With Hedge Fund

      January 11, 2024
    • In Global IP Disputes Called the ‘Robot Wars,’ S&C Secures Settlement for Client Ocado Group plc

      July 24, 2023
    • S&C Obtains Critical Trial Victory for Ocado in Patent Dispute

      December 17, 2021
    • S&C Obtains Dismissal of Securities Lawsuit Against Abiomed

      October 5, 2021
    • S&C Obtains Favorable DOJ Antitrust Business Review for Innovative University Patent Pool

      January 19, 2021
    Read More
    Read More
    Publications, Videos and Podcasts

    Publications, Videos and Podcasts

    • S&C Litigators Author Chapters in Commercial Litigation in New York State Courts

      Books October 28, 2020
    Read More
    Credentials

    Credentials

    Education

    • Columbia Law School, J.D., 1992
    • University of Rochester, B.S., 1989

    Bar Admissions

    • New York
    • New Jersey
    Read More
    Related Practices

    Related Practices

    • Litigation
    • Antitrust
    • Intellectual Property & Technology Litigation
    • International Arbitration and Global Dispute Resolution
    • Media & Telecommunications
    • Securities Litigation
    • Supreme Court and Appellate
    • Technology
    Sullivan & Cromwell LLP Logo

    Sending an e-mail through this web site does not create an attorney-client relationship. You should not send us any information through this web site that you would want treated confidentially.

    Accept
    Sullivan & Cromwell LLP Logo
    • Twitter icon
    • LinkedIn icon
    • RSS Feed icon
    • Podcasts icon
    • Home
    • Contact Us
    • Information Policy Relating to Cookies
    • Privacy Policy
    • California Privacy Policy
    • Website Notice
    • Attorney Advertising Notice
    © 2025 Sullivan & Cromwell LLP