Nippon Shinpan Co. said Monday that personal data of up to 100,000 holders of its NICOS credit cards might have been leaked.
The leak apparently occurred after Nippon Shinpan handed over to a direct-mail forwarding company an optical memory disc carrying the data, including names, addresses and phone numbers, in December, the consumer credit services operator said.
Starting in early March, Nippon Shinpan said it received a series of inquiries from four cardholders who complained they received bills demanding payment for accessing certain Internet sites, even though they had never accessed the sites.
The company said it began a probe because the bills were found to contain the exact same errors as those the four people made in registering their names and other personal data.
The personal data on the four was in a file that contains data on a total of 99,789 cardholders.
The company said it copied the file to an optical memory disc, along with five similar files of personal data before putting the disc into the temporary custody of the direct-mail company.