Marquis, a fintech company based in Texas, has informed multiple U.S. banks and credit unions about a significant data breach that occurred due to a ransomware attack on August 14. The breach has affected at least 400,000 individuals, with the largest impact in Texas, where around 354,000 residents had their data compromised. This incident follows legally mandated disclosures in several states, including Iowa, Maine, Massachusetts, and New Hampshire, revealing the extent of the breach. The stolen data includes sensitive information such as customer names, dates of birth, addresses, and financial details, including bank account and credit card numbers. Social Security numbers were also taken, heightening the potential risks for those affected. Marquis attributed the attack to hackers who exploited a known vulnerability in its SonicWall firewall, although it did not confirm which specific group was responsible. Reports suggest that the Akira ransomware gang may be linked to this attack, as they were known to target SonicWall customers around that time. Marquis has not disclosed the total number of affected individuals or whether it communicated with the hackers or paid a ransom. As more breach notifications are expected, the number of impacted customers may increase. The company serves over 700 banking clients, meaning the ramifications of this breach could extend well beyond the initial disclosures.