Nationwide transforms legacy mortgage system in 10 months

The Business Issue

Nationwide is the world's largest building society, owned by its 24 million members. As a mutual organization, every penny spent is member money, making careful investment critical. Yet in their mortgage business – a sector representing £285 billion in balances – they were running on a core operations platform that they had slowly outgrown.

For 10 years, they supported mortgage operations from application through completion with what they called the Mortgage Sales Case Ownership (MSCO) system. Over time, the system became increasingly difficult to maintain. It carried security and support concerns, lacked documentation, and depended heavily on specialist knowledge. The organization was spending more than £1 million annually simply to maintain the platform.

At the same time, the UK mortgage market was becoming more volatile, customer expectations were rising, and their recent acquisition of Virgin Money made the stakes even higher. The organization needed greater flexibility while continuing to deliver the high level of service its members expected.

The Solution

Nationwide needed to modernize without disrupting their business or forcing 2,000 colleagues to undergo slow retraining. The goal was to move to a supported platform while preserving a familiar experience for the people using it every day.

Working with their partner, Accenture, Nationwide used the Pega Platform^TM to rebuild MSCO on a modern foundation. Because the legacy application had little documentation, the team began by analyzing how the existing system behaved in production, conducting workshops with subject matter experts, and reconstructing workflows and business logic from first principles. Every assumption was reviewed and validated before implementation began.

Nationwide designed the new experience to closely resemble the legacy application to support adoption. According to Nationwide's mortgage technology leadership, the differences were intentionally minimal, allowing colleagues to continue their work with little disruption while the underlying platform was modernized.

The new platform also supports Nationwide's case ownership model, helping ensure work is routed to the right people at the right time while providing a foundation for future modernization efforts across mortgage operations.

The Results

Nationwide completed the transformation in 10 months, significantly faster than the multi-year timelines initially discussed during planning. The project replaced a platform that had been operating for more than a decade and was consuming more than £1 million per year in licensing and support costs.

By moving to the Pega Platform, Nationwide created a more maintainable and scalable environment for mortgage operations. The new platform condensed their operational footprint from a spiderweb of six fragmented components down to a clean spine of four. It united their workflows into a single system, removing key-person dependencies and mitigating operational risk. The organization reduced dependence on a small number of specialists, improved operational resilience, and established a stronger foundation for future change.

Onboarding is now faster and simpler, with 530+ colleagues already active on the new experience. More importantly, Nationwide's members now benefit from faster, smoother mortgage journeys with fewer delays. The building society now has a stable foundation for the next decade, with plans to adopt AI-powered agents and real-time workflow optimization.

Looking ahead, Nationwide plans to continue expanding its use of Pega across mortgage operations as part of its broader modernization strategy.

Want to dive deeper into their journey? Watch their PegaWorld session here.