Nationwide retires 45-year-old core system and moves 15 million accounts to cloud-native platform built on Microsoft Azure
Nationwide retires 45-year-old core system and moves 15 million accounts to cloud-native platform built on Microsoft Azure #
Nationwide Building Society has completed a major core banking overhaul, retiring a legacy platform and moving 15 million customer accounts to a cloud-native system built on Microsoft Azure, according to a feature published by Microsoft’s UK stories team.
Paul Ballard, Nationwide’s Chief Technology Officer, said the transition had to be invisible to members. “We have to do it where people don’t even know it’s happened,” he said. “We don’t disrupt your life.” The decommissioned system was a 45-year-old customer data engine that predates the widespread adoption of personal computers. The migration required rebuilding customer records, moving sort codes, updating card providers, and overhauling branch and digital service journeys at the same time.
Nationwide is the world’s largest building society, with approximately 19 million members across 605 branches. Beyond the 15 million accounts now on the new platform, the institution is also preparing to absorb roughly five million customers from its 2024 acquisition of Virgin Money into the same infrastructure.
When Sri Kanisapakkam joined as Chief Data and Analytics Officer in 2023, Nationwide operated 19 separate data stores across different business lines and teams. The organisation has since consolidated that fragmented estate onto Microsoft Azure and Azure Databricks, creating a unified foundation for analytics and artificial intelligence workloads.
Nationwide has deployed Microsoft 365 Copilot for general productivity and has approximately 2,500 engineers working with GitHub Copilot. On the customer side, the building society previously reported that using GPT-4 within Azure OpenAI to help draft customer letters cut average response times from 45 minutes to between 10 and 15 minutes, with human review required before any AI-generated output is used. Ballard confirmed that Azure AI Foundry will form part of Nationwide’s agent development roadmap. “It’s not about AI doing finance,” one executive noted. “It’s about AI helping finance do its job better.”
The migration completes a multi-year modernisation programme that Group COO Suresh Viswanathan has previously said placed Nationwide in “catch-up mode” relative to digital-native rivals. With current and savings accounts now off the legacy platform, the building society says its focus is on completing the remaining modernisation work, embedding Virgin Money into a unified platform, and strengthening operational resilience. Seven million members log on to its digital channels every day.
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