Tens of thousands of Simplii Financial customers may have had their personal data exposed.
The company issued a news release today saying fraudsters might have gained electronic access to certain personal and account information for 40,000 clients.
Senior Vice President Michael Martin says they have already taken action to enhance their monitoring and security procedures.
The company has pledged to refund 100 per cent of the money lost from an affected bank account.
Clients are being urged to monitor their accounts for unusual activity, and to ensure a complex password is used.