Casa Study: From Hosting to SaaS – Building a Legal Framework for a Major FinTech Transition

Case Study | Commercial & IP | Technology & FinTech | SaaS Agreements

The Client

Our client is one of the UK’s leading providers of bespoke core banking software. Its customer base includes building societies, banks, and co-operative financial institutions throughout the UK. With a significant share of the mutual banking market, they are a business that has consistently pushed the sector forward and reached a point where they needed to evolve to continue growing..

mlplaw were instructed to make that happen.

A Transition That Needed More Than a Solicitor

The instruction was deceptively simple. In practice, this was one of the most technically demanding and commercially sensitive projects our Commercial & IP team has undertaken, involving a large portfolio of regulated financial services customers, a multi-stakeholder consortium structure, and years of established contractual relationships that needed to be preserved, not disrupted.

Legacy hosting agreements had served the client well. But they weren’t designed for the flexibility, data protection obligations, and service delivery realities of a SaaS model. Moving customers across cleanly, confidently, and without triggering costly renegotiation, required a carefully structured legal strategy, not a simple redraft.

What We Did

We approached this as a two-stage project.

1. The first task was to bridge the gap between old and new. Rather than immediately replacing legacy agreements, we drafted bespoke addenda to the client’s existing hosting contracts. These preserved the established commercial relationships while formally accommodating the development and rollout of the new SaaS platform, giving both sides legal clarity during the transition itself, not just after it.
2. The second, larger task was building the framework for what came next. Working closely with the client’s team, we designed and drafted a new Master Services Agreement specifically built around their SaaS delivery model. This wasn’t a template exercise. It was constructed from the ground up to reflect how the platform actually operates and, deliberately, it used the architecture of the existing agreements as a foundation wherever possible.

That familiarity was a strategic choice. Building society customers are sophisticated counterparties, and a wholly unfamiliar contract structure would have created friction where the client needed confidence. By anchoring the new MSA in something recognisable, we reduced the risk of unnecessary pushback before it had a chance to develop.

The MSA addressed the issues that matter most in regulated financial services: clear allocation of responsibilities between the client and its customers, GDPR-compliant data protection provisions, service level commitments and uptime obligations, and the flexibility to accommodate new and evolving product offerings as the SaaS platform grows.

Working Across a Complex Stakeholder Environment

One of the most distinctive features of this project was the multi-stakeholder environment. The client’s customers operated within a banking consortium with its own legal team, its own regulatory requirements, and its own expectations around security and operational resilience.

mlplaw worked collaboratively with that consortium’s legal team throughout. Rather than a negotiation between opposing sides, this was a genuine joint effort aimed at producing agreements that both the client and its customers could stand behind with confidence. The outcome balanced our client’s commercial goals with the consortium’s need for robust regulatory, operational, and security protections. That balance was acknowledged on both sides.

Why this Approach Made a Difference

It would have been straightforward to draft a new MSA and present it to customers as a done deal. The risk – reopening settled positions, generating uncertainty, driving unnecessary negotiation across a large customer portfolio would have been significant.

Instead, by building on familiar structures and working collaboratively with the consortium, the transition landed smoothly. Customers recognised the terms. Continuity was visible. The friction that so often accompanies major contractual change was substantially reduced and with a portfolio of this scale and sensitivity, that translated directly into time and cost saved, and relationships protected.

The Outcome

The client now has a modern, scalable legal framework built for where the business is going, not where it has started. The new MSA accommodates new customers, new products, and the next phase of commercial growth, without requiring a renegotiation from scratch each time.

Not a single existing customer relationship was disrupted in the process. The contractual infrastructure now supports the client’s continued position at the forefront of the UK mutual banking technology market.

What This Means for Technology Businesses in Regulated Sectors

Moving from a hosting model to SaaS is not just a technology decision, it is a legal and commercial one, with real consequences for every customer relationship a business holds. In regulated industries like financial services, where counterparties are sophisticated and continuity matters, getting that transition right requires more than good drafting.

It requires an understanding of the market, the relationships, and the regulatory environment. It requires the ability to work across complex, multi-party structures. And it requires a legal team willing to treat the project as a business challenge. It’s not just a documents exercise.

That is what mlplaw brought to this instruction. And it is what we bring to every technology business navigating this kind of change.

mlplaw’s Commercial & IP team advises technology businesses, FinTechs, and software providers on SaaS agreements, commercial contracts, and IP strategy. To find out how we can support your next transition, get in touch.