The Due Diligence Few Do in M&A — And What It Costs
Most M&A due diligence is a financial exercise. Auditors go through the books. Lawyers review contracts. Risk teams look at liabilities. By the time a deal closes, the acquirer knows the target’s revenue, its debt structure, its legal exposure, and its asset base down to the last detail.
What they usually don’t know is whether the customers will stay.
I was talking to someone recently who’d been through a significant acquisition — the kind that looks clean on paper, strong financials, complementary products, logical strategic fit. What nobody had assessed before the deal closed was what the target company’s customers actually valued about doing business with them. It turned out a lot of it was specific to how that company operated — the responsiveness, the relationship, the feeling of being a big account at a smaller firm rather than a small account at a larger one. Once the acquisition closed and the integration started, those customers began leaving. Not because the product got worse. Because the experience did.
The financial model hadn’t priced that in, because nobody had looked at it.
This is where CX due diligence belongs in an M&A process, and almost nobody does it. Before a deal closes, the acquiring company should have a clear picture of what the target’s customers value most about the relationship, how loyal that customer base actually is versus how loyal it appears to be, and which of those loyalty drivers are at risk of disappearing in an integration. That’s not a survey you send after the deal — it’s research you do before you sign, the same way you’d assess any other material asset.
Customer relationships are an asset. They appear on the balance sheet as revenue, but revenue is a lagging indicator. By the time customers leave, the financial model has already been built on the assumption that they’d stay. The leading indicator is the experience — how customers feel about the company right now, what would make them reconsider, and what an integration announcement is likely to do to their confidence. You can measure that before the deal closes. Most acquirers don’t.
The employee side is equally underassessed, and often more immediately consequential. Two companies combining means two cultures, two sets of expectations, two ways of doing things that felt completely normal to the people inside each one. The employees who built their careers at the target company didn’t sign up to work for the acquirer. Some of them will be fine with the change. Some of them won’t. The ones who won’t are often the ones with the deepest customer relationships — the account managers, the service leads, the people customers actually call when something goes wrong. When they leave, the customers they carried often leave with them.
An EX assessment before integration planning begins isn’t a soft exercise. It’s a retention risk analysis. It tells you which employee segments are most at risk, what they value about their current environment that may not exist post-merger, and what the integration plan needs to protect if it wants to keep the people the business actually depends on. That’s information worth having before you’ve announced a reorg, not after.
The cultural dimension is the one that tends to get the most lip service and the least actual attention. Culture isn’t values statements and office perks — it’s how decisions get made, how conflict gets handled, how customers get treated when something goes wrong, and what employees do when nobody is watching. Two companies can have completely compatible financials and completely incompatible operating cultures, and you won’t find that in the books.
What you will find it in: conversations with employees at multiple levels, journey mapping that shows how each company actually serves its customers versus how it thinks it does, and a systematic comparison of the experiences both companies deliver and the gaps between them. That work takes weeks, not months, and it changes what you build into the integration plan — which is where mergers actually succeed or fail.
The acquirer who called in a CX firm for due diligence told me it was the most useful thing they did in the process. Not because it changed the deal — the financials still drove the decision — but because it told them exactly where to focus the first ninety days of integration to protect the revenue the model was counting on. They knew which customer segments were at risk and why. They knew which employee groups needed the most attention and what they needed to hear. They didn’t spend the first quarter discovering problems they could have mapped before they closed.
Most acquirers find out what their customers valued about the company they just bought by watching those customers leave. It doesn’t have to work that way.