Mark S. Ostrau is Chair of the Antitrust and Trade Regulation Group and a partner in the Intellectual Property and Technology Transactions Groups at Fenwick & West LLP, a Silicon Valley based law firm specializing in high technology industries and matters. He assists high technology companies in acquisitions, licenses and other technology-related commercial transactions and advises clients on a wide variety of antitrust, foreign investment review and other regulatory issues.

Mark's practice includes regularly representing clients before various government antitrust agencies in connection with the U.S. Hart-Scott-Rodino Act and other antitrust aspects of acquisitions worldwide. He has personally handled several hundred filings with the Federal Trade Commission and Department of Justice antitrust sections specifically responsible for high technology matters, including many of the most significant recent transactions in the industry, such as Cisco System’s acquisition of Scientific Atlanta, Symantec Corporation’s acquisition of Veritas Software, Macromedia’s sale to Adobe Systems, Data Domain's sale to EMC, King Digital Entertainment’s sale to Activision Blizzard, Spansion’s merger with Cypress Semiconductor and Concur’s sale to SAP. He has managed numerous HSR “second requests” and related foreign investigations involving market concentration, technology and IP issues, including matters such as Adobe/Macromedia, Cooper/Ocular Sciences, Cadence/CCT, Microsoft/Intuit and VeriSign/Thawte. Mark has also represented numerous domestic and foreign clients in connection with matters before the Committee on Foreign Investment in the United States.

He also provides daily advice and counseling on the issues and business practices critical to technology industries, including R&D collaborations, patent pools and standard setting, product interoperability, patent and copyright misuse, package licensing and bundling, marketing and distribution, and pricing and discrimination. He has represented scores of IT, Internet and life sciences companies, from startups to industry leaders. In addition to Cisco Systems and Symantec, notable companies he has represented include ASML, CooperVision, GoPro, Intuit, Sun Microsystems, Veritas and VeriSign.

Mark has authored numerous articles and presented many speeches and educational seminars on a variety of antitrust and licensing topics relevant to technology industries, and is often quoted in industry and general media on antitrust topics. He was a contributing author and/or editor for the ABA Antitrust Section handbooks Intellectual Property Misuse: Licensing and Litigation (2000), Premerger Notification Practice Manual (2015), and Antitrust in Technology Industries (2018).

Mark has been listed annually in Best Lawyers in America for antitrust law since 2009 and as a Northern California Super Lawyer since 2006 by Super Lawyers, a Thomson Reuters publication.

While attending Stanford University, Mark clerked with the Antitrust Division of the U.S. Department of Justice.​​​​​​​​​​