Nationwide Bets on Data Work Before It Trusts Agents

Nationwide Building Society is rolling Copilot through finance and code, and its technology chief still says the mutual is nowhere near autonomous agents. Paul Ballard, the chief technology officer, put the order of work in plain terms in August 2026: staff are faster, the return is not priced, and agents that act without a person in the loop are not on the floor.

That is a harder wager than a Copilot rollout. The society has to finish a core replacement, hold a customer-service lead it has spent years building, and move Virgin Money onto Nationwide platforms without members feeling a merger in their app.

Ballard Says the Society Is Nowhere Near Agents

Ballard’s public brief with Microsoft is that Nationwide will use Microsoft 365 Copilot, GitHub Copilot, Azure OpenAI and later Microsoft Foundry to build agents that can talk to its systems. His operational brief is narrower. In August he said the society was nowhere near autonomous agents, and that human checks stay on every live use.

The biggest risk is complacency with this stuff. If it works 99 times, brilliant. If the hundredth time it doesn’t, how do you make sure you spot it?

Paul Ballard, Chief Technology Officer, Nationwide Building Society

He also said the thing they have not nailed is the value. Teams can see people using the tools more often and finishing work faster. They cannot yet say what that does to the bottom line. “Every pound that we spend is a pound of our customers’,” he said, which is why Nationwide joined Microsoft’s early access programme with about 300 users and still had only about 1,000 premium Copilot licences at the start of 2026.

The society has since put workplace AI in front of around 16,000 staff. About 1,000 people in the combined Nationwide and Virgin Money finance team hold premium Microsoft 365 Copilot licences. About 2,500 engineers use GitHub Copilot. Ballard’s line on that spend is that it should help the existing workforce produce more for customers, not cut the headcount that serves them.

Eighteen Million Savings Accounts Left the Old Core

The Copilot seats sit on top of work that has little to do with chat. Ballard says Nationwide has already moved 15 million customers off its former core banking engine and replaced a 45-year-old customer data system. The annual report for the year ended 31 March 2026 says the society completed a multi-year migration of 18 million Nationwide-branded savings accounts from a legacy system onto a modern SAP platform, and that Faster Payments now run across two cloud platforms.

Ballard’s test for that work is that members should not feel it. “We have to do it where people don’t even know it’s happened,” he said. “We don’t disrupt your life.” For a mutual that now serves over 24.5 million customers, with 605 Nationwide branches and a promise that also covers Virgin Money’s 91 branches until at least 2030, a noisy cutover would show up first as missed payments and locked apps, then as a crash in the service scores the society treats as a product.

THE MOVES ALREADY ON THE BOOKS

Underlying profit before tax for that year rose 9% to £2,026m from £1,852m. Statutory profit before tax fell to £1,490m from £2,302m because the prior year included a one-off gain on the Virgin Money purchase. Integration spend in the year was £127m, and the society has already said that bill will rise as customer systems start to move.

The 6.8 Million Customers Still Waiting to Move

The legal step is done. The systems step is not. Nationwide completed its £2.9bn purchase of Virgin Money on 1 October 2024. The High Court approved the business transfer on 23 February 2026. On 2 April 2026 the society completed the largest non-ring-fencing banking business transfer ever made in the UK, moving about 6.8 million Virgin Money customers across under Part VII of the Financial Services and Markets Act 2000.

Accounts that moved still run under the Virgin Money name for now. Nationwide’s own transfer page tells those customers that day-to-day banking does not change because of the legal step. Brand and platform migration is the next phase. Preliminary results said that work would commence in 2026. The annual report said the aim is to complete it in material terms between 2028 and 2029. Nationwide-branded business banking is due in the first half of 2027.

Early September 2026 job ads for a London product manager to put Virgin Money products onto Nationwide’s platform are the ground-level version of that timetable. The hire is about sort codes, cards, journeys and ledgers, not a chatbot.

THE VIRGIN MONEY CLOCK

1. 1 October 2024: Nationwide completes the £2.9bn purchase of Virgin Money UK.
2. 23 February 2026: The High Court approves the Part VII scheme.
3. 2 April 2026: About 6.8 million customers transfer legally to Nationwide.
4. June 2026: Nationwide says it will cut 600 overlapping roles as operations merge.
5. 2026: Customer migration to Nationwide-branded systems is due to begin.
6. First half of 2027: First Nationwide-branded mainstream business banking products are due.
7. 2028 to 2029: Material completion of the brand and systems move is the stated aim.

UK banking already has a template for what happens when a core move is treated as a weekend event. TSB’s main migration ran over 20 to 22 April 2018 and hit about 5.2 million customers. Online, phone and branch channels failed even though the data itself moved. The Financial Conduct Authority and the Prudential Regulation Authority later fined TSB a total of £48.65 million, and the bank paid £32.7m in redress. It did not call the episode business as usual until December 2018. Ballard’s “you don’t notice” line is the opposite of that weekend.

Why 19 Data Stores Had to Die First

Sri Kanisapakkam, chief data and analytics officer, joined in 2023 and found 19 separate data stores. The Microsoft-facing version of the story is that those stores now sit on one cloud platform. The Databricks case study is more specific: in 12 months Nationwide migrated 17 of 19 data warehouses onto the Databricks Data + AI Platform, first on Azure, with AWS in the plan.

Kanisapakkam’s reason is trust, not novelty. “AI is not magic,” he said. “It needs to understand how your data is organised and how your data is structured. The data has to be trusted first before you can say your AI is trusted.” On the Databricks page he put the ownership model in one line: Nationwide is not a bank, it is a building society that runs on mutuality, and when it does well the members take the gain.

THE LAKEHOUSE IN FIGURES

• Assets on the book: £367.9 billion, with a prior-year return of £2.8 billion in member value.
• People on the data: more than 5,000 internal users, plus Talk to Data for about 70 to 80 executives and their direct reports.
• Feed volume: more than 3,000 daily data feeds dropped onto the lakehouse.
• What is trusted: access opened to nearly 70% of trusted sources, with 15% of those already used for real-time calls.

That base is already used to map about 120 customer journeys and to match Virgin Money records. Nitin Kulkarni, CIO for data and AI, said many models still run monthly or quarterly and that the next step is to score them more often. The stack is built to run across clouds on purpose. Kanisapakkam said they needed a platform that could serve every persona and work across multiple cloud providers. Ballard has used the same word, optionality, for models: different models for different jobs, no single-vendor lock as costs and rules move.

Forty-Six Percent of Finance Staff Use It Daily

Katy Barker-Cook, director of future capability and operations in finance, said finance was one of the first group functions to put Copilot across the combined Nationwide and Virgin Money team. The jobs it takes are dull on paper and expensive in hours.

WHAT COPILOT IS DOING IN FINANCE

• First drafts: Rough notes become a usable starting text instead of a blank page.
• Meetings: Summaries and action lists are pulled out of calls that used to be retyped by hand.
• Messages: Routine emails and updates are shaped faster across two former organisations.
• The stitch work: Barker-Cook’s point is that finance is often fragmented, not technically hard, and that the time sits in joining the pieces.

In a recent internal poll, 46% of finance respondents said they used Copilot every working day and 36% said they used it several times a week, which is 82% using it at least that often. Barker-Cook has been careful not to overclaim while the habit is still forming. She says colleagues already see faster drafting and more consistent writing, and that the tool does not replace judgement in a function where accuracy is the product. “It shortens the path to a good first draft,” she said.

The one numbered saving the society has been willing to put on a customer-facing task is older than this Copilot wave. From January 2025 it has said GPT-4 inside Azure OpenAI helps generate customer letters, cutting average handling from 45 minutes to 10 to 15 minutes, about 66%. A person still reads the output before it goes out. That is the same human-in-the-loop rule Ballard now applies to agents.

Members Pay for Tools the Society Cannot Price

Because Nationwide is a mutual, the Copilot bill is a member bill. Ballard’s “no FOMO” rule is the investment policy that follows from that: AI is not the answer to everything, and the society will not buy seats to keep up with a press release. He has said they want to see where the value is before they spend the next pound.

June 2026 put that claim next to a harder number. Nationwide said it would cut 600 jobs in the first major round tied to the Virgin Money takeover, aimed at overlapping back-office work rather than the branch roles covered by the promise through 2030. The same year it opened more than one million personal current accounts, lifted branch current-account openings by 20%, and took £10.3bn of mortgage net lending. Which? ranked its mortgage journey first among 21 lenders.

The service lead is now national, not just a peer-group habit. On 7 July 2026 the Institute of Customer Service said Nationwide scored 87.3 out of 100 in the UK Customer Satisfaction Index, first of all brands, up from 86.3 and fourth place a year earlier. John Lewis scored 87.1. first direct scored 86.0. Between 1 October and 31 December 2025, Nationwide took 64,527 net current-account gains through switching. Banks and building societies as a sector sat above retail in the index for the first time since it launched in 2008. Jo Causon, the Institute’s chief executive, tied that climb to training, technology, competition and the FCA’s Consumer Duty rules from 2023.

A botched platform move would spend that score quickly. That is why the unglamorous work still sits in front of the agent work, and why Ballard keeps repeating that the hundredth failure is the one that matters.

Agents for Crime Checks and Mortgages Wait

The agent list is real and it is not live. Ballard has pointed to knowledge assistants for frontline staff, tools that help business analysts write requirements, helpers for architects, and later agents for anti-money laundering, customer due diligence and mortgage advice. Microsoft Foundry, which unifies agents, models, and tools under one Azure resource with tracing and evaluations, is the factory those builds would use. Nationwide already runs an AI council across technology, security, legal and procurement, and an AI centre of expertise built with IBM Consulting on Azure OpenAI.

WHAT IS LIVE, WHAT IS NOT

• Live now: GPT-4 letter drafts with a human review, Microsoft 365 Copilot in finance, GitHub Copilot in engineering, Talk to Data for a small executive group, and the lakehouse that feeds them.
• Named, not autonomous: agents for crime checks, customer due diligence, mortgage advice, analyst requirements and architect support, all still described as future work with a person in the loop.

Fairer Share payments for eligible Virgin Money members are due from 2027, which is also when Nationwide-branded business banking is supposed to appear. The systems those products will run on are the ones still being stitched. Until that stitch holds, an agent that can talk to “our systems” is talking to two banks that share a court order and not yet a single platform.

Ballard’s closing brief on the merger is that Nationwide has to come out of integration modern and future fit. The bet underneath that sentence is smaller and easier to audit. If members still do not notice the move when the 2028 to 2029 window closes, the plumbing held. Only then does the hundredth agent action have a system it can trust.