It said on Wednesday that all personal and significant amounts of health claims data of all its customers were compromised in the breach reported this month, a day after it warned the number of customers affected would grow. Medibank, which covers one-sixth of Australians, said the estimated cost did not include further potential remediation or regulatory expenses. "Our investigation has now established that this criminal has accessed all our private health insurance customers' personal data and significant amounts of their health claims data," chief executive David Koczkar said in a statement. Medibank, which also withdrew its fiscal 2023 policyholder growth forecast, reported an after-tax profit of about A$394 million for fiscal 2022 in August. A person claiming to be behind the Optus hack later withdrew the demand over concerns about publicity.

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