Marquis, a technology company used by hundreds of banks to analyze and visualize customer data, says hundreds of thousands of people had their personal and sensitive financial information stolen in ransomware attacks last year.
The Plano, Texas-based fintech company has notified at least 672,075 people that hackers stole their information in an August 2025 cyberattack, according to a list from the Maine Attorney General's Office.
More than half of those affected live in Texas, according to a separate data breach notification filed in the state.
This disclosure provides a previously unreported picture of the number of people affected by the breach.
The breach allowed hackers to steal bank customers' names, dates of birth, and addresses. The hackers also stole customers' financial information, including bank accounts, debit numbers, and credit card numbers. Marquis said the hackers also stole customers' Social Security numbers.
In February, the fintech company sued its firewall provider, SonicWall, alleging that a security flaw allowed hackers to steal sensitive information about the company's firewalls, which the hackers used to breach Marquis' network, steal data, and deploy ransomware.
Marquis said in its lawsuit that SonicWall created a vulnerability that allowed hackers to steal customers' firewall configuration backup files, including Marquis's.
Marquis did not immediately comment when contacted by TechCrunch.