New Delhi, Oct. 22 -- State Bank of India (SBI) said on Wednesday that it had suffered "an incident involving the loss of certain data", stating that 3,897 customer records containing personal information of customers have been identified so far in a larger trove of about 375,000 records on the dark web. In a disclosure to the stock exchanges, the bank said it was alerted to this data breach on October 16 by its threat intelligence provider, the Defence Cyber Agency and Cert-In. The exposed information reportedly included registered mobile numbers, dates of birth, names, gender, email addresses, residential addresses, branch and CIF identifiers, lead IDs, and metadata linked to loan records and other files. SBI said it had activated its incident response protocols and engaged an independent Cert-In-empanelled agency to establish the authenticity of the data, its source and the extent of the exposure. It said the incident has no material impact on its core operations, financial performance or business continuity. The filing does not say how the data left the bank's systems. HT reached out to the ministry of electronics and IT (MeitY), Cert-In and SBI, but did not immediately receive a response. The 3,897 records are a tiny fraction of SBI's base of more than 500 million customers. But the figure comes from what SBI calls a "preliminary analysis". It accounts for about 1% of the roughly 375,000 records said to be online. The disclosure does not say what the remaining records contain, whether they relate to SBI customers, or how many people they cover. Addressing its customers in a post on X, SBI said, "...we advise that the incident has impacted a very small number of customers. We wish to assure that it does not have any material impact on Bank's IT and Core business operations, financial performance or business continuity. Customer balances are completely safe and we are taking all possible steps to protect the interests of our valued customers." The digital rights advocacy Internet Freedom Foundation (IFF) said that on the day SBI received the alert, a threat-monitoring account on X flagged a claim by a group calling itself "Siriusim". The group claimed to have released 375,000 rows of SBI data and 2,722 PDF documents, including loan applications and account-opening forms. SBI's disclosure does not mention the documents. IFF said SBI has not stated it has informed any affected customer, and filing is silent on this. It noted five days passed between the alert and the filing. IFF called on SBI to notify every affected customer directly by SMS, email and letter, in English, Hindi and regional language of the branch....