Interview
The dual-core revolution:
Accelerate growth without the risk of a full rip-and-replace
14 January 2026
Interview with Mark Geneste, Chief Revenue Officer, Mambu
For too long, banking leaders have felt trapped. They know they need to launch modern digital propositions to compete, but they are paralysed by the fear of touching their legacy cores. They assume that innovation requires a high-risk, multi-year "rip and replace" project. This paralysis is costly.
While incumbents plan, challengers execute.
But the narrative is changing. The most successful banks are discovering they do not need to change everything to change something. We sat down with Mark Geneste, our Chief Revenue Officer, to discuss why the era of the "big bang" migration is over and how a dual-core strategy is finally closing the gap between ambition and execution.
Everyone in banking is talking about the pressure to grow. What is changing right now?
Mark Geneste: The pace of change has fundamentally shifted. Capabilities like BNPL, digital lending, embedded payments, and modern account products have evolved from differentiators into basic expectations. The problem is that most banks still rely on legacy cores that were never designed for continuous innovation. That creates a real tension between a bank’s growth ambition and their execution reality.
Why does this matter now, not in five years' time?
Mark Geneste: Because standing still is the fastest way to fail. Banks that plan multi-year core transformations risk losing market share and revenue while fintechs and digital challengers launch, iterate, and learn in months. Today, speed to market is the minimum requirement to protect revenue and grow.
This is why the dual-core strategy is gaining traction. Can you tell us more about it?
Mark Geneste: Think of dual core as the antidote to the “rip and replace” nightmare. For risk-averse institutions, it offers a pragmatic path to modernisation. Instead of overhauling your entire legacy estate overnight, you simply spin up a composable, cloud-native platform alongside it, such as Mambu.
This separation changes the game. The legacy core continues to handle the core business and stable operations it was built for, while Mambu powers new, high-growth propositions at speed.
So, it removes the biggest constraint: time?
Mark Geneste: Exactly. With a dual-core architecture, banks move from idea to market in months rather than years. They effectively isolate innovation from the slow-moving legacy core. This approach drastically reduces delivery risk and allows the bank to generate new revenue streams immediately without destabilising existing systems. It turns modernisation from a single, high-risk gamble into a controlled and profitable growth strategy.
Can you share examples of banks doing this successfully?
Mark Geneste: Absolutely. Look at ABN AMRO. They modernised SME lending through New10 in just a few months. They also launched a digital bank for teens, BUUT, in just a year. Bank Muamalat launched Malaysia’s fully Shari'ah-compliant digital bank, ATLAS, at impressive pace. Ibercaja Banco spun up a new personal lending proposition without touching the legacy core. For Ualà, it took only two months to implement our platform and within 15 months they went live. Two years later, they had issued over 1 million cards, scaling across Argentina, Mexico and Colombia.
Different markets, different strategies, but the same result: speed.
Some critics might argue dual core is just a temporary workaround. How do you respond?
Mark Geneste: That is a dangerous misconception. Dual core is far from a shortcut. It is a strategic approach we call progressive modernisation. What often starts as a single product launch becomes the foundation for broader transformation. Banks use Mambu to prove value, unlock revenue, and then gradually migrate legacy products over time. This is how you make transformation sustainable and commercially viable rather than betting the bank on a massive migration project.
What role does Mambu play in this model?
Mark Geneste: We act as an agility partner. Our true Saas, cloud-native platform allows banks to run multiple propositions in parallel, integrate seamlessly with existing cores, and scale as needed.
Clients utilising Mambu in a dual-core setup prove that speed, flexibility, and reliability can coexist. We provide the composable building blocks that allow them to build what they need, when they need it.
What advice would you give CROs and CEOs planning for growth in 2026?
Mark Geneste: The question is no longer whether to modernise but how. If growth depends on launching new products, waiting for a full core replacement is rarely the fastest or safest path. I advise leaders to stop looking for the perfect time to change everything and start looking for the fastest way to change something.
By adopting a dual-core architecture, banks can:
- Move faster: Launch new products from idea to market in months.
- Reduce risk: Keep innovation separate from the stability of the legacy core.
- Experiment safely: Test, learn and iterate before scaling.
- Unlock revenue: Generate new income streams immediately without disrupting operations.
Speed and growth in banking are non-negotiable. The legacy core is not the constraint if you don't let it be. Dual core unlocks agility, revenue, and controlled transformation. If you are exploring new lending, digital banking, or payments propositions and want to move faster without replacing your core, this is a conversation worth having.
Get in touch to start your progressive modernisation journey. Or, if you’d prefer to see the platform in action first, join one of our upcoming live demos.
© Mambu 2026