Barely months after coming up for air over the fake accounting scandal, Wells Fargo is facing further scrutiny, this time over a data breach that saw the accounts of 50,000 of its wealthiest clients accidentally leaked to a former employee.

The documents, handed over to an attorney as part of a lawsuit involving two brothers, one a Wells Fargo employee and the other a former employee, included at least 50,000 customers' names, Social Security numbers and sensitive financial data.

The data was dispatched by the legal firm representing Wells Fargo with no confidentiality clause attached. The 1.4GB file was passed to a third party vendor who failed to delete the non-essential client data before handing it on to the court.

Wells Fargo has asked for return of the files but the plaintiff in the case isn't playing ball. His lawyer says his client plans to keep the CD secure and confidential for now as they "evaluate his legal rights and responsibilities".