William (Will) Díaz litigates and counsels clients on antitrust cases, obtains Federal Trade Commission (FTC) and Department of Justice clearance on mergers, and defends clients in government investigations. Will has significant experience in the interplay between the antitrust and intellectual property laws and the issues that crossover into both areas, including standard-setting activities, patent pools, fair, reasonable and non-discriminatory (FRAND) licensing issues and patent misuse. He also has handled numerous litigations and transactions in the biotech, pharmaceutical and medtech industries.

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  • Represented Amgen, Inc., in securing antitrust clearance for its $10.4 billion acquisition of Onyx Pharmaceuticals, Inc., which is the largest acquisition in Amgen’s history and one of the largest life sciences transactions in the industry
  • Represented Amgen, Inc., in defeating class action litigation involving allegations of tying and bundling (Warren General Hospital v. Amgen Inc.)
  • Represented Mars, Inc., in its acquisition of the Wm. Wrigley Jr. Company, a global transaction involving a number of the best known confectionary sugar brands such as Skittles® and Starburst®

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  • The Legal 500 US 2019
  • Federal Trade Commission, Award for Meritorious Service
  • Southern California Rising Star 2015


  • IP Symposium, 2014 co-chair and moderator and 2013 panelist
  • American Bar Association, Antitrust Section, IP Committee’s E-Bulletin 2012 to 2014, contributing editor
  • Standards Essential Patents – Enforcement, Antitrust, Patent Prosecution and Licensing Issues, Intellectual Property Management Roundtable 2013, panelist

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Georgetown University Law Center, JD, 2000
University of Florida, BS, magna cum laude, 1997


Courts / Agencies
US Court of Appeals for the Ninth Circuit
US District Court for the Central District of California
US District Court for the Northern District of California

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William Díaz

Insights & Events / Media

The National Law Journal / March 21, 2016

Intellectual Property & Technology Law Journal / May 2015

DOJ Issues Business Review Letter Pertaining to SSO Policy on Standard Essential ...

Wolters Kluwer AntitrustConnect Blog / May 4, 2015

DOJ Issues Business Review Letter Pertaining to SSO Policy on Standard-Essential Patents ...