EXPERIENCE

Representative matters include:

Product Liability and Mass Torts

• Defending Monsanto at trial in Washington state court against claims brought by 15 plaintiffs alleging injuries from PCB exposure, including securing complete defense verdicts on 11 of the 15 plaintiffs’ claims
• Defending AbbVie in multiple bellwether trials in federal and state court related to the company’s testosterone replacement therapy product, including securing a complete defense verdict at trial in Illinois state court   
• Defending Pfizer in national litigation related to the company’s antidepressant, including securing complete defense verdicts in the first two bellwether trials in Missouri and Pennsylvania state courts
• Defending ExxonMobil in various climate-change related tort lawsuits brought by states, counties and municipalities

Cybersecurity and Data Protection

• Defending the owners of the Ashley Madison website in a consumer fraud class action over a data breach
• Representing a healthcare company in federal regulatory investigations related to data privacy and digital advertising
• Representing a hospital in a state regulatory investigation related to data privacy

Insurance

• Defending CNA and affiliates in numerous lawsuits in state and federal courts seeking coverage for business losses related to the COVID-19 pandemic

Financial and Securities Litigation

• Defending investment bank underwriters, including Citigroup, J.P. Morgan and Morgan Stanley, in securities fraud class action lawsuits in state and federal court related to initial public offerings
• Defending Bank of New York Mellon in various civil and regulatory matters related to the company’s foreign exchange services
• Defending UBS against fraud claims related to residential mortgage-backed securities

Investigations

• An investment management company in an internal investigation related to accounting issues
• A financial institution in an internal investigation related to accounting issues
• An investment adviser as a third-party witness in a federal regulatory investigation

Other High-Profile Litigation and Investigations

• Representing the New Jersey Governor in the successful defense of a lawsuit challenging an investigation into state tax incentive programs
• Representing the National Basketball Players Association in an internal investigation related to allegations of nepotism and conflicts of interest

Yahonnes has worked, on a pro bono basis, with the NAACP Legal Defense and Educational Fund on matters related to voting rights and racial justice, the American Bar Association on matters related to affirmative action in higher education, and the Bronx Defenders and the Sentencing Project on matters related to criminal justice.

Yahonnes is co-president of the board of trustees of Prep for Prep, a member of the Board of Trustees of Choate Rosemary Hall, and a member of the Yale Law School Fund Board.

He was named to the “40 & Under Hot List – Northeast” in 2020 and 2021 and recognized as a “Future Star” in the 2025 edition of Benchmark Litigation.