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Sharon Mayo has more than 25 years of litigation and counseling experience in complex commercial litigation, primarily in the pharmaceutical, consumer products and payment card industries. Sharon has extensive experience in defending and resolving class actions, mass actions and multi-district litigation proceedings– involving claims of products liability, unfair competition and unfair and deceptive practices (including Cal. Bus. & Prof. Code §17200), antitrust, partnership and contractual disputes, and business torts.

Sharon has a strong commitment to pro bono service, and has represented individuals and organizations in a wide array of proceedings. Most recently, she represented Planned Parenthood in a widely reported, six-week federal jury trial against anti-abortion extremists, helping to obtain a multi-million dollar verdict on claims for RICO, trespass, fraud, illegal recording, and contract violations.

Ms. Mayo was recognized as a Northern California Super Lawyer for business litigation from 2012-2016. She is also an AV-rated attorney, a peer-awarded honor given by Martindale-Hubbell.


  • International pharmaceutical company in global product liability actions related to Covid-19 vaccine, including obtaining dismissal of action under Public Readiness and Emergency Preparedness Act.
  • Pfizer in product liability matters concerning talc in products pending in California state courts; obtained summary judgment in one such matter pending in Alameda County Superior Court.
  • Pfizer in litigation involving allegations of cerebellar atrophy related to the antiepileptic drug Dilantin®.
  • Bristol-Myers Squibb in products liability mass actions concerning Abilify®.
  • Bristol-Myers Squibb and Sanofi in multiple products liability mass actions in California and New Jersey concerning Plavix®. Plavix Product and Marketing Cases, Judicial Council Coordination Proceeding 4748; In Re: Plavix Mktg., Sales Practices & Prods. Liab. Litig. (No. II), MDL No. 2418.
  • Bristol-Myers Squibb and Sanofi in action by the Attorney General of the State of Hawaii concerning Plavix®.
  • Hologic, Inc. in medical device product liability claims.
  • Astrazeneca Pharmaceuticals, LP in class action asserting overcharges under a federal drug discount program (see County of Santa Clara v. Astra USA, et al., 2006 WL 2193343 (N.D. Cal. July 28, 2006); 2006 WL 1344572 (N.D. Cal. May 17, 2006); 428 F.Supp.2d 1029 (N.D. Cal. 2006); Astra USA, Inc. v. County of Santa Clara, 131 S. Ct. 1342 (2011) (holding that third-party beneficiaries to pharmaceutical pricing agreement with the government could not sue pharmaceutical manufacturers to enforce the contract; action dismissed)).
  • Pharmaceutical company in multidistrict litigation involving tens of thousands of suits nationwide. Managed a docket of 2000+ cases.


Daily Journal
"California Lawyer of the Year" — Complex Civil Litigation (2020)
Northern California Super Lawyers (2012-2016)



  • J.D., Loyola Law School, Los Angeles
  • B.A., Claremont McKenna College, cum laude


  • California
  • Supreme Court of the United States
  • U.S. Court of Appeals for the Ninth Circuit
  • U.S. Court of Appeals for the Eleventh Circuit
  • U.S. Court of Appeals for the Federal Circuit
  • U.S. District Court, Central District of California
  • U.S. District Court, Eastern District of California
  • U.S. District Court, Northern District of California
  • U.S. District Court, Southern District of California


  • Public Commissioner, WASC Senior College and University Commission
  • Member, Bar Association of San Francisco
  • Member, Association of Business Trial Lawyers
  • Advisory Board Member, Berger Institute for Individual and Social Development, Claremont McKenna College
  • Advisory Board Member, LexisNexis California (Matthew Bender)