Japan's Dai Nippon Printing Co. (7912.T: Quote, Profile, Research) said on Monday a former contract worker stole nearly 9 million pieces of private data on customers from 43 clients including Toyota Motor Corp. (7203.T: Quote, Profile, Research).
Dai Nippon, one of Japan's largest commerical printing companies, said the confidential information included names, addresses and credit card numbers intended for use in direct mailing and other printing services.
Spokesman Ichiro Yagi said the company had begun discussions with customers about compensation but it was not clear how much it will have to pay.
Dai Nippon said the employee stole client data between May 2001 and March 2006 by copying information on to floppy disks and other recording media.
The company launched an investigation last year following the emergence of an Internet shopping scam in which the former employee allegedly sold 150,000 articles of data to a criminal group.
Dai Nippon Printing announced the theft and the arrest of the former employee on February 20.
But further investigation since then led to the discovery of new leaks and the stolen data total increased to 8,637,405 pieces of data.
Dai Nippon said there were no reports of the newly discovered pieces of stolen data being passed on to a third party.
The stolen data includes about 1.5 million articles on customers of American Home Assurance Co., 1.2 million on UFJ Nicos Co. (8583.T: Quote, Profile, Research)., 580,000 on Aeon Co (8267.T: Quote, Profile, Research). and 270,000 on customers of auto giant Toyota Motor.
Shares of Dai Nippon closed down 0.6 percent to 1,744 yen, against a 0.75 percent rise on the benchmark Nikkei share average (.N225: Quote, Profile, Research).