TORONTO (AP) _ More than 180,000 customers of a Canadian insurance company have been warned about possible identity theft after a subsidiary of IBM lost a computer hard drive containing personal information, the president of the insurance company said Thursday.

Kathy Bardswick, president and chief executive of the Co-operators Group Ltd., said a security breach might have exposed the banking details, social insurance numbers and other personal data of its customers.

The information was stored on a hard drive belonging to data management firm ISM Canada _ a subsidiary of IBM Canada _ that was discovered missing on Jan. 16 from the company's offices in Regina, Saskatchewan.

Letters warning of the security breach went out to more than 180,000 Co-operators clients last week, Bardswick said.

``We are urging our life and pension clients to be vigilant regarding their personal information, and to notify their financial institutions of any unusual activity,'' Bardswick said.

Co-operators is the first company to acknowledge that its information was included on the hard drive. The Saskatchewan government also lost private information from some of its departments.

ISM spokesperson Anne Mowat declined to say how many other companies have been affected by the theft.

``We're very concerned because this is a serious matter. Police authorities are treating this as a theft and we are cooperating,'' Mowat said.

Mowat said the hard drive was ``in a secure area within a secure area.''

Bardswick said the information could be used by a fraud ring to commit criminal activity. She said there have been no signs yet of any illegal activity.

The company is working with credit agencies to help clients monitor their bank and credit card activity for any signs of fraud.

Regina police Sergeant Rick Bourassa also said there been no reports of anyone's information having been used improperly.

``It could simply be a case of wanting a piece of hardware and not wanting to pay for it,'' Bourassa said.