Back in January, we argued that early post‑merger integration (PMI) would be decisive for value realisation in 2025 - the factor that separates a good deal on paper from a great business in practice. As the year closes, that view has only strengthened. Deal dynamics evolved, financing conditions shifted, AI accelerated both diligence and delivery, and boards demanded clearer value pathways earlier in the journey. The strongest outcome came where leaders treated integration as strategy execution, preparing for Day 1 long before signing.
This reflection takes a pragmatic look at what shaped Mergers and Acquisitions (M&A) in 2025: what held true, what surprised many, and the questions every executive team should be asking as they plan for 2026.
2025 M&A lessons: What held true for successful PMI
In our outlook, we emphasised that bringing integration forward - into the thesis, into diligence, and even into the board pack, would be the ballast that steadied deal programmes in an uncertain year. That proved right. The organisations that turned promise into performance did five things consistently well:
- Aligned early on a few, testable value theses, each with numbers that could be owned by the leaders accountable for delivery.
- Defined their integration “north star” - target operating model, governance, Key Performance Indicators (KPIs) - before signing, ensuring Day 1 decisions were fast and coherent.
- Sequenced around customers and revenue first, making early choices that protect run‑rate revenue and reduce churn.
- Treated employee experience and culture as an investment, not a communications plan - minimising uncertainty, setting clear principles for roles, and equipping managers to lead change credibly.
- Used AI to accelerate diligence, design and delivery - not to replace leadership judgement.
Common pitfalls: Why M&A value leakage occurred in 2025
Even sophisticated deal teams hit avoidable turbulence. The patterns were familiar:
- Speed mismatches: moving too fast where complexity was high making re‑work inevitable - or too slow where customer‑facing interlocks were simple, letting value leak.
- Underpowered Integration Management Offices (IMOs): governance that tracked progress but didn’t make decisions, leaving workstreams to mark their own homework and delaying risk removal.
- Change saturation: running business-as-usual change, transformation, and PMI in parallel without a clear view of capacity, stretching critical teams and extending timelines.
- Unknown unknowns: limited insight into processes, data, and technical debt which drove hidden integration costs and messy handoffs between diligence and delivery.
- KPI gaps: synergies tracked offline rather than built into the operating rhythm, making it hard for leaders to see impact and intervene early.
Each of these challenges is solvable with clearer intent up front, realistic critical paths, and a pragmatic view of what must be true for value to land.
The M&A questions to ask now for 2026
Use these questions as a leadership playback to align your board, executive team and integration team on what matters most next.
AI and technology integration
- Where will AI deliver the fastest payback in the integrated business - for example in customer operations, pricing, sales enablement, software development, knowledge management - and what data foundations must be in place for day‑one deployment?
- Are we applying AI to the integration itself - diligence synthesis, codebase analysis, process mapping, training content - to accelerate timelines without compromising risk?
Customers, revenue and go‑to‑market
- What is our detailed revenue defence plan for the top 50 customers across both firms - who engages whom, with what message, offering what continuity and what new value?
- Where do go-to-market overlaps create confusion, and how will we align coverage, pricing and incentives within the first two quarters post‑close?
People, leadership and culture
- What are the three to five culture non‑negotiables we will uphold and which few behaviours will we stop to build trust quickly?
- Do middle managers have the clarity, authority and coaching to lead through ambiguity, or are we expecting them to cascade messages without support?
Governance and decision‑making
- Is the Integration Management Office empowered to decide and remove risk, or does it operate mainly as a reporting layer? What decisions will we make weekly, and what will we deliberately defer?
- Where will we pilot and iterate (agile), and where will we standardise and lock early, and are those choices explicit?
Operating model, data and architecture
- Do we have a single, accessible map of core processes, data domains, and systems - including clear decisions on what we’ll adopt, adapt or retire?
- Have we agreed on the golden sources of data and the near‑term interoperability patterns that ensure customer and financial truth within the first quarter?
Value creation and KPIs
- Are synergy targets realistic, owned by accountable leaders, and embedded in monthly performance reviews - measuring both value and adoption?
- What will we define as “early value” by the end of Q2, and what is the minimal set of changes to achieve it without creating legacy complexity?
A pragmatic M&A integration plan for 2026
Based on hundreds of conversations with executives and investors this year, a credible 2026 plan has four clear beats:
1. Start with customers and cash-
- Protect the run‑rate: identify the top 50 accounts, align account teams, script the outreach, and stabilise SLAs.
- Pick three “early-value” moves, for example: cross‑sell bundles, unified pricing, channel rationalisation, and fund them properly.
- Define the target operating model: decision rights, spans and layers, finance cadence, KPI tree, and test in one business unit before scaling.
- Make system choices within an 18‑month lens: adopt where possible, integrate where needed, retire where sensible. Prioritise finance and customer data first and plan transitions end to end to ensure business continuity throughout PMI.
- Stand up a true IMO with authority to decide, unblock and re‑sequence; make it a talent magnet, not an admin desk.
- Invest in leaders: equip them with the messages, artefacts and coping strategies to lead through uncertainty.
- Deploy AI where strong data and controls already exist: service, sales, and knowledge, and dedicate a small cross‑functional team to integration accelerators that save time every week.
Leaders who follow this rhythm realise two advantages: value that shows up by the end of the second quarter, and the organisational confidence to sustain momentum beyond it.
Final thought - and a simple next step
2025 proved once again that M&A is a means, not an end. The market rewarded conviction, discipline and execution, and penalised slow or shallow integration. 2026 will bring more of the same: greater selectivity, more creative financing, more AI as both a deal driver and a delivery enabler, and more pressure from boards to prove value early.
If you’re planning a deal, or already mid‑integration and aiming to accelerate value, bring your executive team together for a 90‑minute, brutally honest playback on the questions above to generate a focused 100‑day plan that connects strategy to operating reality.
As we said at the start of the year: integrate earlier, decide faster, deliver what matters. It worked in 2025. It will matter even more in 2026.
