PLANNING A CORE BANKING IMPLEMENTATION: 9 DECISIONS THAT SHAPE THE OUTCOME
How a core banking implementation is planned often decides how it ends. The plan establishes the team that will deliver the work, the accountability structure that holds it together, the dependencies that have to be managed, and the gaps that need to be closed before delivery begins. When planning is treated as a documentation exercise rather than the phase that pressure-tests these things, the decisions get deferred to the worst possible moment: mid-flight.
Banking system implementation planning is also where the project earns the trust of the organization that will live with the outcome. Done well, it builds confidence that the work can be delivered. Done poorly, it sets up a project where every challenge surfaces late and feels like a surprise.
This article covers nine considerations that shape a credible plan, from team composition through to vendor readiness assessment.
The Bottom Line
Planning is the phase that decides which problems get solved cheaply before the project starts and which get expensive later.
A capable team is more important than the methodology. The team can adapt the methodology to the project. The reverse rarely holds.
Ancillary systems planning belongs in the foundation, not the side notes. Underestimating this layer is one of the most consistent causes of timeline slippage.
A mapped current state is the only honest starting point. Designing a future state from an unknown current state is how scope creep begins.
Vendor readiness deserves the same scrutiny as your own. A prepared institution and an underprepared vendor produce the same delayed outcome as the reverse.
1. Assemble the Right Team
Internal expertise is valuable, but internal teams should never assume they know better. Strong implementations bring in external advisors who have run comparable programs before, alongside the internal subject matter experts who know the institution. The combination produces decisions that are credible inside the organization and grounded in what actually works elsewhere.
The first question a project owes itself an honest answer to is: who has the experience to run this, and where do the gaps need to be filled from outside? Getting that answer right shapes every decision that follows.
2. Define the Accountability Structure
Once the team is in place, the accountability structure determines whether the project moves at the speed it needs to. Divide the work into streams. Assign ownership of each stream to a named individual. Build in the autonomy to make decisions inside that stream, alongside the governance that coordinates across streams. The article on banking system implementation governance covers how that structure should be set up, and how it should evolve as the project moves through its phases.
A poorly structured project tends to default to informal power centers, where decisions accumulate around the most senior or most vocal person rather than being distributed across accountable workstreams. That pattern is hard to fix once it sets in.
3. Consider Project Size and Methodology
The size, cost, and duration of the project determine the methodology that fits it. Some implementations work best with a Waterfall structure, where each phase finishes before the next begins. Others work better with Agile or SAFe, particularly when requirements are likely to evolve. The right methodology depends on the size of the project, the maturity of the requirements, the vendor's preferred delivery model, and the institution's tolerance for change in flight.
The decision should be deliberate, not inherited from a vendor pitch or from a prior project that bears only superficial resemblance to this one.
4. Allocate Resources and People
Implementation success rests heavily on the people allocated to the work. The skills required vary by phase: requirements and design in the early phases, integration and testing later, operational readiness toward the end. Match the people to the phase.
Confirm that the internal team members pulled onto the project have a plan for returning to their original roles when the work is done. Without that plan, the institution carries the cost of the implementation in operational capability long after go-live. External specialists belong in the plan from the outset, not as a reaction when a gap is discovered.
Building the right team and resourcing plan for a complex implementation is a discipline in itself. 2Oaks' Strategic Advisory and Planning services help institutions structure both together.
5. Align Business and Technical Strategies
Acquiring a banking system is a technical exercise. Implementing it well is a business exercise. The plan needs to reflect both.
Engage senior business stakeholders early, while there is still room to shape the project. Their support is required for the budget, the resourcing, and the operational changes the new system will demand. If they are introduced to the project after the design decisions are made, they are being asked to absorb the consequences without having been part of the decisions.
The new system will also force a re-examination of business processes. Some will need to change to fit the new system. Others can be preserved through configuration. A few will require genuine customization. The planning phase is where those distinctions get drawn and agreed.
6. Prepare Ancillary System Support
A core banking system does not operate in isolation. Payments platforms, online banking, financial crime tools, reporting systems, and a long list of ancillary applications all depend on the core. The planning phase is where their requirements get scoped, not where they get discovered.
For each ancillary system, the plan should answer three questions. Will it integrate with the new core, or be replaced? Who owns that integration on the institution's side and on the vendor's side? What is the timeline dependency between that work and the core implementation? The system selection article covered why ancillary systems belong in the evaluation, not after it. Planning is where that scoping gets operationalized.
7. Map the Current State
Designing a future state from an unknown current state is the most consistent way to produce a project that is constantly rediscovering its own scope.
A clear picture of how the institution operates today identifies the gaps the new system will close, the processes that need to be redesigned, and the technical dependencies that planning has to account for. The mapping does not need to document every workflow in exhaustive detail. It needs to capture what matters: the processes the new system will replace, the integrations that will be impacted, and the operational realities the future state has to absorb.
8. Prime Change Management and Communications
Change management and communications start in the planning phase, not at user training. The communications plan should reach every stakeholder group, from the executive team through to the front-line employees who will use the new system every day.
The article on what every bank needs to know before replacing its core system covers why that engagement has to start before the project gets underway, not when it is most of the way through. The cost of late communication shows up as resistance during cutover and adoption failure after.
9. Assess Vendor Readiness
Vendor readiness deserves the same scrutiny as your own. A readiness assessment with the chosen vendor should identify gaps in technical capability, organizational maturity, and resource availability before the project begins.
The questions are practical. Does the vendor have a team ready to start when the project starts, or are they hiring against this engagement? Has their proposed approach been tested in a comparable context? What is their actual track record on commitments of this scale? An institution that is ready to begin and a vendor that is not produces the same delayed outcome as the reverse.
For a broader external view of how leading institutions sequence planning decisions in core banking transformations, McKinsey's research on how to get a core banking transformation right is a useful reference. Several of the mistakes the authors describe are planning failures rather than execution failures.
Key Questions to Ask Before the Project Starts
Before committing to a project of this scale, the planning team should be able to answer the following with confidence:
Which of the nine considerations covered in this article is currently the weakest in your preparation?
Does the team running this implementation have direct experience of comparable projects, internally or through external advisors?
Are your business stakeholders engaged in shaping the project, or are they waiting to be asked?
Have ancillary systems been scoped, owned, and sequenced in the plan?
Has your vendor's readiness been assessed independently, not just self-reported?
If any of those surface uncertainty, the right response is to address it now. Gaps in the planning phase compound quickly once delivery begins.
Ready to begin your implementation journey? 2Oaks helps financial institutions plan and prepare for success across every phase of a core banking implementation. Get in touch to start the conversation.
This article is adapted from Transforming Banking: An Introduction to Implementing a New System, by Andrew Mills and Bruce Hogg of 2Oaks Consulting.
Learn more about 2Oaks' Program Delivery and Governance practice and how we support institutions through the full implementation lifecycle.
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FURTHER READING
McKinsey & Company: How to get a core banking transformation right: Eight mistakes to avoid. A detailed look at the planning and execution failures most commonly responsible for missed timelines and cost overruns in core banking programs.
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2Oaks emerged from deep within the banking sector, where our founders personally navigated the challenges of core system modernization. This hands-on experience shaped our unique approach to technology consulting -one that combines technical expertise with practical wisdom. We're not your typical consultancy. As a vendor neutral partner, we work exclusively for our clients' interests across banking, financial services, retail, and public sectors.
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