Prosper – 17,605,276 breached accounts

In September 2025, Prosper announced that it had detected unauthorised access to their systems, which resulted in the exposure of customer and applicant information. The data breach impacted 17.6M unique email addresses, along with other customer information, including US Social Security numbers. Prosper advised that they did not find any evidence of unauthorised access to customer accounts and funds, and that their customer-facing operations were uninterrupted. Further information about the incident is contained in Prosper’s FAQs.