Res judicata, or claim preclusion, is grounded in the principle that disputes, once fully and fairly adjudicated, should not be relitigated. New York courts apply a broad transactional approach to claim preclusion, barring not only claims that were actually litigated in a prior action, but also those that could have been raised in that action.

In Cantor Fitzgerald & Co. v. PEI Global Partners Holdings LLC, 2026 N.Y. Slip Op. 00080 (1st Dept. Jan. 13, 2026), the Appellate Division, First Department, affirmed the dismissal of a complaint under CPLR 3211(a)(5) based on res judicata.