Recognized in Best Lawyers since 2026 Mr. Portnoy is a business litigator who handles major commercial disputes for a wide range of companies and individuals. From large-cap industry leaders to cutting-edge start-ups, Mr. Portnoy’s clients rely on him to deliver efficient, effective solutions for their most complex legal matters. He is Co-Chair of the firm’s Securities Team. He also focuses his practice on high-stakes breach of contract disputes and professional negligence claims in the financial and legal services industries. Recent and current examples include the defense of major pharmaceutical manufacturers and C-suite executives against various 1934 Act claims, representation of a securities rating agency in a contract dispute concerning bond pricing technology, and the defense of multiple prominent legal service providers against claims of professional negligence. Mr. Portnoy brings to bear ability and perspective informed by more than 15 years of experience in private practice, service as in-house counsel, and work for federal judges, both trial and appellate.
Mr. Portnoy regularly litigates in federal and state courts throughout the country, handling complex business and commercial litigation in areas that include:
- Securities fraud
- Insider trading
- Common law fraud
- Professional negligence and liability
- Breach of contract
- The Racketeer Influenced and Corrupt Organizations (RICO) Act
- The Federal Tort Claims Act
- Mass tort
- Fraudulent conveyance
- Business reorganization
