A data breach at SitusAMC, a New York-based technology provider, has compromised sensitive client information from major U.S. banks, including JPMorgan Chase, Citigroup, and Morgan Stanley. The breach, discovered on November 12, 2025, involved unauthorized access to SitusAMC's systems, potentially exposing client accounting and legal documents. SitusAMC is enhancing its security measures and collaborating with law enforcement to address the incident.