Information leaked from Benesse Corp. includes personal data on people who never had a contract with the company , its parent company said Tuesday . According to Benesse Holdings Inc. , the data not only dealt with customers of the subsidiarys mainstay education services , but also information related to the firms lifestyle business services collected at its events and other occasions . The leaked data was stored in a smartphone used by a system engineer arrested last week for allegedly copying trade secrets from the company , Chikara Matsumoto , chief risk management officer of Benesse Holdings , said at a news conference . So far , it is known that personal information on some 23 million people leaked from the subsidiary . Benesse Corp. said Monday that data on some 22.6 million people was found on the systems engineers smartphone . In addition , information on some 400,000 people was leaked through unconfirmed channels . The police investigation is nt complete , which means further data leaks could come to light . Initially , Benesse Holdings said that information on up to some 20.7 million customers might have been compromised based on lists obtained from name - list brokers . The corporate group then found that user information was compromised at the Benesse LifeSmile Shop , an online shopping site for pregnant women and mothers , and Benesse Womens Park , a social networking site for women . The newly found data include the estimated due dates of some 200,000 babies . Tokyo police arrested Masaomi Matsuzaki , 39 , last Thursday on suspicion of downloading and copying the personal data of Benesse customers onto his smartphone from the Tokyo branch of affiliate Synform Co. Authorities seized the smartphone and a memory card from Matsuzaki and matched data on the phone and storage device with Benesse customer information . Matsuzaki admitted selling the data to name - list traders and gambled away the money , according to the police . Also Tuesday , Benesse Holdings convened a panel of experts to begin investigating the steps leading up to the theft and draft measures to prevent future data leaks . The panel , headed by lawyer Hideaki Kobayashi , will also investigate the responsibilities of the firms compliance officers , the company said . ;