Approximately 8.2 million U.S. customers of Cash App Investing have been notified of a data breach carried out by a former employee of the mobile payment service provider.

Block, Cash App’s parent company, disclosed the breach in a regulatory filing with the Securities and Exchange Commission on Monday. The unauthorized access occurred Dec. 10, 2021, and the information exposed included current and former customer full names, brokerage account numbers, brokerage portfolio values, brokerage portfolio holdings, and/or stock trading activity for one trading day.