The billion-dollar blind spot in M&A

Every year, companies spend trillions of dollars on mergers and acquisitions. Bankers run models. Lawyers comb contracts. Operations teams map supply chains. IT audits architecture. In most cases, marketing does little. 

That the function responsible for communicating why the deal matters to the people that fund it (customers) is absent is both negligent and costly. 

M&A failings are commonplace

M&A failures are well-established (70%-90%), with McKinsey reporting that due diligence overlooks as much as half of potential merger value. Overestimated synergies, weak diligence, poor integration execution, and cultural misalignment are oft-cited culprits.

While this is not news, it persists against a backdrop of an accelerating deal market. According to Bain & Company, M&A deal value hit its second highest level on record in 2025, many of the megadeals representing more than half of the acquirer’s own market cap. 

Marketing remains an afterthought, which represents opportunity

Research suggests that marketing is only involved pre-close in 50% of major deals. Part of the challenge is that, as is too often the case across the discipline, marketing is thought of purely as a communications exercise. A press release. An updated website. A few social posts.  

The reality is that M&A marketing integration is a set of interconnected decisions with direct revenue consequences. It involves:

• Brand strategy: Which brand survives? Are they combined or do they run in parallel? How fast does the transition happen? What does it signal to existing customers?
• Value proposition: What does the combined entity offer that neither company could alone? Can customers understand it? Will they care?
• Customer segmentation: Do the customer bases overlap? What does that mean for pricing, channel strategy, and coverage?
• Key account management: How are your most valuable customers handled during the transition? What are they being told? Who’s telling them?  
• Marketing technology: How are two different tech stacks combined, rationalized, or retired? How will critical data be preserved in the process
• Messaging consistency: Are sales, marketing, and customer service telling the same story?

Every one of these is as much a revenue question as it is a marketing question. And every one is routinely deprioritized in favor of cost synergies, org design, and process integration.

• Where marketing is absent, customers are neglected. And common approaches to M&A diligence and post-merger integration bring this to bear:
• M&A is driven by bankers, lawyers, and CFOs. The metrics that define success are financial (e.g., EBITDA multiples, synergy estimates, IRR). Marketing leaders are rarely part of the core deal team, and when they are engaged, it's usually to manage the announcement.
• Due diligence historically focuses on financial, legal, and operational issues. Customer experience is treated as secondary even though three in five consumers report being customers of a company that went through M&A. 
• Post-merger marketing efforts are consumed by internal work on organization structure, reporting lines, process mapping. Precious little energy is focused on customer-facing activities at a time when external signals matter most.
• Integration management is focused on capturing cost synergies first because they're fast and measurable. Revenue synergies, which require marketing to define and execute, are longer-dated and harder to model. They come second and often never arrive.  
• When two companies merge, the acquirer's brand typically wins not because the data supports it, but because either the acquirer's executives won't accept anything else or it’s simply assumed. The resulting brand strategy may be incongruent with what customers actually value.

McKinsey surveyed 50 leaders with combined experience across more than 100 integrations, each valued above $1 billion. Companies that applied a structured marketing integration approach captured revenue synergies at a rate 1.5 to 2.0 times higher than those that didn't. And yet that same research confirms that most integrations still don't do it.

MarTech is a particular problem few prepare for

The MarTech landscape has grown to over 15,000 solutions as of 2025 and the average marketing organization now manages 120-plus tools. According to industry research, companies are wasting roughly two-thirds of their MarTech spend (about a quarter of total marketing budget) on capabilities nobody uses. What’s more, 47% of MarTech decision makers cite the complexity of their tech stacks and data integration as the primary barriers to realizing ROI on their technology investments. 

This is the environment in which two organizations are attempting to combine and are seeking to do so without a plan for rationalizing those stacks. When two companies combine without a MarTech integration roadmap, the result is characterized by layered complexity, data silos, duplicate vendor contracts, and a marketing organization that can't execute a coherent customer experience. This is not a tech inconvenience; it’s a revenue problem.  

When marketing technology gets considered at all during integration, it's usually as a systems consolidation exercise, not a revenue question. The CMO's view on which platforms enable the go-to-market model is rarely central to that conversation.

Customers watch but don’t wait

Customers are not passive observers of an M&A transaction. They're reading the signals, and the signals they usually receive during a merger are silence, mixed messaging, and confusion.

The math on what this costs is stark. The companies paying deliberate attention to their top customer segment in the post-close period earned almost 60% higher revenue synergies than companies that didn't. Key accounts want to know who their contact is, what service levels they can expect, what new offerings are coming, and when. Companies that answer those questions proactively retain and expand those accounts. Companies that don't leave a door open for competitors to walk through.

What getting it right looks like

Strong marketing integration involves a number of considerations that begin pre-close and are executed intentionally, at speed, post-merger:

• Defining the combined entity’s value proposition
• Assessing and refining customer segmentation and targeting against the combined company’s market 
• Proactively managing high-value accounts through the transition
• Delivering fresh value early, often, and consistently to customers
• Taking a data-based approach to brand strategy rather than letting political realities determine the course
• Scoping marketing’s integration workload so execution quality holds

Amazon's acquisition of Whole Foods is a textbook example of what good looks like. Within days of close, Amazon rolled out price reductions on popular items, made Prime savings available in-store, and began installing Amazon Lockers across locations. The customer-facing roadmap was prepared in advance, not improvised after close. Customers immediately understood what the deal meant for them and revenue followed.

Lenovo's acquisition of IBM's PC business is another strong case. Rather than defaulting to IBM's brand recognition, which would have been the politically easy choice, Lenovo analyzed brand equity across its target segments and determined that ThinkPad's equity was strong enough to carry the transition. That decision has proven durable with Lenovo still going to market under the ThinkPad name. 

Standard operating procedure is the enemy

Marketing should be engaged during due diligence to evaluate brand equity, customer segment fit, MarTech infrastructure, and the messaging risk the combination creates. And it should also play a critical role in post-merger integration as a co-architect of the revenue synergy plan. Brand strategy should be decided with customer research, not executive preference. Martech integration should be framed as a revenue enablement question from the start.

Companies that treat marketing as a Day 1 priority in integration capture measurably more of what the deal was supposed to deliver. Companies that treat it as a follow-on are eroding the customer relationships the deal was designed to strengthen.

With the blind spot understood and the fix straightforward, the primary variable becomes whether deal teams will adjust their rote approaches to act on it.  

Sources: McKinsey & Company, Bain & Company, PwC, Wharton School, MergerWare, MarTech/Semrush State of Your Stack 2025, chiefmartec.com.