For more than four decades, Fenwick & West LLP has helped some of the world’s most recognized companies become, and remain, market leaders. From emerging enterprises to large public corporations, our clients are leaders in the technology, life sciences and cleantech sectors and are fundamentally changing the world through rapid innovation.  MORE >

Fenwick & West was founded in 1972 in the heart of Silicon Valley—before “Silicon Valley” existed—by four visionary lawyers who left a top-tier New York law firm to pursue their shared belief that technology would revolutionize the business world and to pioneer the legal work for those technological innovations. In order to be most effective, they decided they needed to move to a location close to primary research and technology development. These four attorneys opened their first office in downtown Palo Alto, and Fenwick became one of the first technology law firms in the world.  MORE >

From our founding in 1972, Fenwick has been committed to promoting diversity and inclusion both within our firm and throughout the legal profession. For almost four decades, the firm has actively promoted an open and inclusive work environment and committed significant resources towards improving our diversity efforts at every level.  MORE >

FLEX by Fenwick is the only service created by an AmLaw 100 firm that provides flexible and cost-effective solutions for interim in-house legal needs to high-growth companies.  MORE >

Fenwick & West handles significant cross-border legal and business issues for a wide range of technology and life sciences who operate internationally..  MORE >

At Fenwick, we are proud of our commitment to the community and to our culture of making a difference in the lives of individuals and organizations in the communities where we live and work. We recognize that providing legal services is not only an essential part of our professional responsibility, but also an excellent opportunity for our attorneys to gain valuable practical experience, learn new areas of the law and contribute to the community.  MORE >

Year after year, Fenwick & West is honored for excellence in the legal profession. Many of our attorneys are recognized as leaders in their respective fields, and our Corporate, Tax, Litigation and Intellectual Property Practice Groups consistently receive top national and international rankings, including:

  • Named Technology Group of the Year by Law360
  • Ranked #1 in the Americas for number of technology deals in 2015 by Mergermarket
  • Nearly 20 percent of Fenwick partners are ranked by Chambers
  • Consistently ranked among the top 10 law firms in the U.S. for diversity
  • Recognized as having top mentoring and pro bono programs by Euromoney


We take sustainability very seriously at Fenwick. Like many of our clients, we are adopting policies that reduce consumption and waste, and improve efficiency. By using technologies developed by a number of our cleantech clients, we are at the forefront of implementing sustainable policies and practices that minimize environmental impact. In fact, Fenwick has earned recognition in several areas as one of the top US law firms for implementing sustainable business practices.  MORE >

At Fenwick, we have a passion for excellence and innovation that mirrors our client base. Our firm is making revolutionary changes to the practice of law through substantial investments in proprietary technology tools and processes—allowing us to deliver best-in-class legal services more effectively.   MORE >

Mountain View Office
Silicon Valley Center
801 California Street
Mountain View, CA 94041

San Francisco Office
555 California Street
12th Floor
San Francisco, CA 94104

Seattle Office
1191 Second Avenue
10th Floor
Seattle, WA 98101

New York Office
1211 Avenue of the Americas
32nd Floor
New York, NY 10036

Shanghai Office
Unit 908, 9/F, Kerry Parkside Office
No. 1155 Fang Dian Road
Pudong New Area, Shanghai 201204
P.R. China
+86 21 8017 1200

Mark S. Ostrau

Chair, Antitrust & Unfair Competition

Partner, Intellectual Property  

Mountain View 650.335.7269


Mark S. Ostrau is Chair of the Antitrust and Unfair Competition 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 transactions, and advises clients on a wide variety of antitrust, marketing, intellectual property and misuse 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 two hundred to two hundred and fifty 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.

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 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 (upcoming).

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.