Mitsubishi UFJ Securities Co. said Wednesday that an employee sold the personal data of more than 49,000 of its customers to three dealers of personal data lists and that the employee was dismissed earlier in the day.

The key brokerage arm of Mitsubishi UFJ Financial Group Inc. said it has notified police and is preparing to file a criminal complaint against the 44-year-old, who was the deputy chief of the computer systems department.

The dismissed employee took the personal data of a total of 1,486,651 customers home without authorization. He then sold information relating to 49,159 customers to the three dealers for ¥328,000 to repay his consumer loans, Mitsubishi UFJ Securities Managing Director Koji Maeda said.