Marquis discloses data breach affecting over 672,000 people

Marquis, a financial technology (fintech) company based in Plano, Texas, has disclosed that a ransomware attack in August 2025 resulted in hackers who stole their information, affecting over 672,000 people. The company, which is used by hundreds of banks to analyze and visualize their customers’ data, is currently notifying 672,075 people of the data theft. The details of the incident emerged through a listing filed with Maine’s attorney general’s office, which serves as a US state regulatory body.

Following the incident, Marquis initiated legal action against its security vendor. In February, the fintech company sued SonicWall, its firewall provider—which provides network security barriers—accusing the firm of security failings. Marquis alleges that SonicWall created a vulnerability that allowed hackers to steal firewall configuration backup files, including those belonging to Marquis. According to the lawsuit, hackers used this critical information about the firewalls to compromise Marquis’ network, steal data, and deploy the ransomware.

The breach has broad geographic implications, particularly in the company’s home state. According to a separate data breach notice filed in Texas, more than half of all the affected individuals live in that state. The disclosure provides the most complete public accounting to date of the security incident, which had not been previously reported.

The compromised data includes highly sensitive personal and financial records. According to the filings, the breach allowed hackers to steal banking customers’ names, dates of birth, and postal addresses. In addition to these identifiers, the hackers stole customers’ financial information, including bank account, debit, and credit card numbers. Marquis also stated that the hackers took customers’ Social Security numbers.

When contacted by TechCrunch, Marquis did not immediately comment on the lawsuit or the breach notification.

Why it matters

This disclosure provides the clearest view yet of a previously unreported ransomware attack on a financial technology company serving hundreds of banks, highlighting the legal fallout between the firm and its security provider. The case underscores the growing operational and legal risks that banks face when third-party security infrastructure is compromised.