Kyushu Electric Power Transmission and Distribution: backup media missing

Kyushu Electric Power Transmission and Distribution disclosed a missing backup SSD on June 8. It was last confirmed stored April 27 and found missing May 26, but the exact loss date is unknown. Its July 8 review revised the initial maximum of 10.9 million accounts to 13.54 million records: 10.03 million individual and 3.51 million corporate/other records, including 7.14 million continuing contracts. Identical name/address records were deduplicated, but contract and equipment records remain, so this is not a population count. Data included customer names, supply addresses, usage and some phone numbers, excluding bank, card and email data. No leakage was confirmed. The SSD had no encryption or password protection and was kept in an unlocked server-room cabinet; the company identified storage and contractor-supervision failures.