Marketing’s role in M&A due diligence: What gets missed when they’re not at the table
Marketing in M&A due diligence
In mid-sized M&A deals, marketing can get involved after the transaction is announced or on Day 1, when brand, customer, and cultural risks have already taken root.
That’s a mistake.
While financial and operational due diligence is thorough, the commercial risks – brand confusion, customer attrition, cultural misalignment, and fragmented communication – are harder to quantify. But they can quietly erode value, stall integration, and trigger early losses in both revenue and trust.
Bringing a marketing leader into the due diligence phase helps the deal team get a clearer, faster view of how the combined business will operate and where the real risks lie, beyond the spreadsheet.
What marketing brings to due diligence
These aren’t soft signals or “nice-to-haves.” They’re operational, commercial, and brand-critical issues that impact customer retention, revenue, and integration success.
Brand equity and reputation risk
Marketing assesses each brand’s market position – leader, challenger, niche, or undifferentiated. They flag brand misalignment, sentiment shifts, and any reputational baggage. They’ll also apply a customer lens to how the acquiring brand is perceived, which is especially important in deals involving multiple brands or market overlaps.
Customer base health
While the deal team looks at revenue, marketing digs into customer behaviour. Are customer segments growing or shrinking? How concentrated is revenue? Are there signs of churn or dissatisfaction? These questions give a more accurate picture of the stickiness and risk.
Commercial relationships and people risk
In B2B deals, client relationships are often tied to individuals – account managers, founders, or long-standing rainmakers. Marketing can help identify those connections and work with HR or leadership to assess how to best retain trust.
Market positioning and brand overlap
If multiple brands are involved, marketing evaluates how they’re positioned. Do they compete or complement? Could they cannibalise each other? And are customers clear on what’s staying, changing or disappearing?
Channel and content mapping
Businesses often have a tangle of websites, social channels, content libraries, databases. Marketing can audit what’s working, what’s duplicated, and where inconsistencies may confuse or delay customers post-deal.
Internal comms and culture fit
M&A messaging often focuses externally. But internal alignment makes or breaks performance. Marketing and HR can work together to assess tone and values, and prepare Day 0 communications that build trust and land well with staff.
Competitor lens
Marketing teams are often closest to competitor activity and messaging. They can anticipate how competitors might respond, where they’ll exploit uncertainty, and what positioning needs to be protected.
What gets missed when marketing isn’t involved
- Conflicting brand positioning
- Customer confusion about value and offer
- Product or service duplication
- Disconnected internal and external messaging
- Relationship continuity risks
- Unused or duplicated digital assets
- Cultural friction that escalates post-deal
- Martech complexity that slows or derails execution
A practical checklist for deal teams and marketing leads
- Assess brand sentiment – internal, customer, market
- Map customer churn, concentration and growth
- Identify relationship owners and retention risk
- Audit brand positioning and portfolio structure
- Review messaging and digital presence
- Assess martech, CRM, and content management tools for overlap
- Partner with HR on internal alignment
- Pre-test messaging before Day 0
Bottom line
Marketing due diligence isn’t about running campaigns or updating the logo. It’s about pressure-testing the deal’s commercial reality of the deal before customer and cultural risk bite.
Marketing is fast-moving, deeply integrated, and broader than many deal teams realise. It touches platforms, people, perception, and performance.
Bring a marketing lead in early. Not after the deal but before the risk sets in.
Need a quicker version? Read the short guide here.
