About 900,000 current and former Origin Energy Ltd. customers had their data accessed in a security breach, the latest in a string of cyberattacks on major Australian companies and essential-service providers. It began examining a possible threat in early July, but initially determined it was not credible, the energy retailer said in a statement on Tuesday. New information emerged on July 22 indicating a breach may have occurred. “We are working with cyber security and forensic specialists to ensure the incident is contained,” Chief Executive Officer Frank Calabria said in the statement. Origin shares fell 1.1%, underperforming the Australian benchmark’s 0.3% decline as Asia Pacific stocks dropped 3.2%.