Sean Prosser's practice focuses on all aspects of securities litigation. Mr. Prosser, a former SEC enforcement attorney, defends companies and their officers and directors, as well as public accounting firms and broker-dealers, in shareholder class action, derivative, and corporate control lawsuits, and in enforcement investigations and proceedings by the SEC, FINRA, stock exchanges, California Department of Corporations, DOJ, PCAOB and other regulatory agencies. He also represents companies, including special committees and audit committees, in connection with internal investigations. During his career, Mr. Prosser has defended numerous public companies and their executives in federal securities class action and state derivative lawsuits. He has represented clients in a broad range of industries, including life sciences, financial services, computer software and hardware, life sciences, and consumer products.
Mr. Prosser is recognized by Legal 500 (US) for his expertise in Merger Litigation, and by Best Lawyers in America (2010-2016) for his expertise in Securities Litigation, Mergers & Acquisitions Litigation, SEC Enforcement Litigation, and Corporate Compliance & Corporate Governance Law. He also was named Best Lawyers' 2016 San Diego Corporate Governance Law "Lawyer of the Year." Mr. Prosser also is listed in San Diego SuperLawyers 2010-2015. Mr. Prosser is a member of the Board of Editors for the Corporate Counselor and a member of the Association for Securities and Exchange Commission Alumni (ASECA). He is also a member of the California Bar Association and the San Diego Bar Association. He is admitted to practice in California, before the U.S. District Courts for the Central and Southern Districts of California, and before the U.S. Court of Appeal for the Ninth Circuit.
In re Mentor Corp. Merger Litigation — In re Mentor Corp. Shareholder Litigation (Santa Barbara Super. Ct.; State of Minnesota District Court, County of Hennepin). Represent Mentor Corporation and its directors in shareholder class actions arising from $1.1-billion acquisition by Johnson & Johnson. Successfully obtained orders denying motion for preliminary injunction in California action, and staying parallel Minnesota action. Won summary judgment in clients’ favor following discovery.
In re Netlist, Inc. Securities Litigation — In re Netlist, Inc. Securities Litigation. Represented Netlist, Inc. and its officers and directors in connection with state and federal shareholder litigation. Favorably settled following successful federal motions to dismiss. 2009 WL 1293690 (C.D. Cal. Apr. 17, 2009); 2008 WL 2356699 (C.D. Cal. May 30, 2008).
In re Cogent, Inc. Merger Litigation — In re Cogent, Inc. Merger Litigation (Los Angeles Super. Ct.; C.D. Cal.; Delaware Chancery Court.) Represent Cogent, Inc. and its directors in shareholder class action lawsuits filed in California state and federal courts and in Delaware Chancery Court arising from $943 million acquisition by 3M. Successfully defeated plaintiffs’ motion to enjoin transaction (No. 5780-VCP, 2010 WL 3894991 (Del. Ch. Oct. 5, 2010)) and obtained stay of parallel California lawsuit. (Pending).