New York Supreme Court Denies Motion to Dismiss in Opioid Litigation Against McKinsey, Allowing Claims to Proceed

New York, NY — March 2026 — Attorneys from Zimmer, Citron & Clarke successfully argued in front of the Supreme Court of the State of New York which denied a motion to dismiss in County of Westchester et al. v. McKinsey & Company, Inc. This ruling allows claims brought by New York municipalities arising from the opioid crisis to proceed.

Photo by Arthur Cauty

The action was brought by a group of counties, towns, and cities alleging that McKinsey & Company played a central role in advising opioid manufacturers, including Purdue Pharma, on marketing and sales strategies that increased the distribution of opioid medications. Plaintiffs allege that those strategies promoted opioids as safe and effective while contributing to widespread addiction and significant public harm.

In a March 2026 decision, the Court rejected McKinsey’s argument that the claims were barred by a prior enforcement action brought by the New York Attorney General. The court held that the municipalities were not parties to the prior action and may pursue claims based on their own distinct injuries.

The Court further concluded that the complaint adequately pleads multiple causes of action, including negligence, fraud, deceptive business practices, false advertising, and public nuisance. In particular, the court found that plaintiffs sufficiently alleged that McKinsey’s conduct could give rise to a duty of care to third parties and that its alleged role in designing and implementing marketing strategies contributed to the harms suffered by the municipalities.

Ultimately, the Court dismissed only the unjust enrichment claim, while permitting the remaining claims to proceed.

Together with Napoli Shkolnik, Zimmer, Citron & Clarke represents plaintiffs in the litigation, opposed the motion to dismiss, and focused on defending the legal sufficiency of the municipalities’ claims and the viability of their theories of liability at the pleading stage.

The decision allows the case to move forward to discovery and further proceedings, where the municipalities will seek to establish McKinsey’s role in the development and implementation of opioid marketing strategies and the resulting impact on their communities.

The case is County of Westchester et al. v. McKinsey & Company, Inc., Supreme Court of the State of New York, Suffolk County, Index No. 4000004/2021.