---
title: "JPMorgan Chase, Citi and Morgan Stanley Customers Impacted As Massive Third-Party Data Breach Hits Banks: Report"
type: "News"
locale: "en"
url: "https://longbridge.com/en/news/267937549.md"
description: "A cyberattack on tech vendor SitusAMC exposed sensitive data of JPMorgan Chase, Citi, and Morgan Stanley customers. The breach occurred on November 12, 2025, with unauthorized access to customer records and legal documents. SitusAMC is enhancing security measures and cooperating with law enforcement, while reviewing impacted files and updating affected clients."
datetime: "2025-11-29T18:05:54.000Z"
locales:
  - [zh-CN](https://longbridge.com/zh-CN/news/267937549.md)
  - [en](https://longbridge.com/en/news/267937549.md)
  - [zh-HK](https://longbridge.com/zh-HK/news/267937549.md)
---

> Supported Languages: [简体中文](https://longbridge.com/zh-CN/news/267937549.md) | [繁體中文](https://longbridge.com/zh-HK/news/267937549.md)


# JPMorgan Chase, Citi and Morgan Stanley Customers Impacted As Massive Third-Party Data Breach Hits Banks: Report

A cyberattack on a New York-based tech vendor has led to the exposure of sensitive customer data, including records belonging to three of the largest banks in the US.

In a notice, SitusAMC says it became aware of a cybersecurity incident on November 12th, 2025, when an unauthorized third party gained access to its systems and stole files that may include customer accounting records, legal documents and other corporate data.

The New York Times, citing people familiar with the matter, reports that JPMorgan Chase, Citi and Morgan Stanley were among the clients notified by SitusAMC that their customer data may have been stolen.

SitusAMC provides technology, strategic outsourcing, talent and advisory solutions to major banks, lenders, investors and government agencies.

The IT vendor says it is taking measures to harden its system’s defenses while cooperating with law enforcement authorities. SitusAMC says it is still in the midst of reviewing impacted files and will continue to provide updates to customers involved.

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- [JPMorgan Chase & Co. (JPM.US)](https://longbridge.com/en/quote/JPM.US.md)
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- [Morgan Stanley (MS.US)](https://longbridge.com/en/quote/MS.US.md)

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