Culture in M&A: What Deal Specialists Know — and Choose to Ignore

Why does culture remain the blind spot of mergers and acquisitions?

After giving voice to employees, managers, HR leaders, and executives, this article shifts perspective. It explores the cultural dimension of M&A through the eyes of those who structure the deals: M&A specialists. Consultants, bankers, and advisors offer here a lucid — sometimes brutal — view of what is known, yet rarely integrated before signing.

Their feedback was strikingly direct. Almost brutal in its simplicity.

And that is precisely why I choose to address this message at the level where everything is decided: you — CEO, deal sponsor, guardian of value… and ultimately, the person responsible for what will happen to teams after the signature.

An Open Letter to Leaders About to Sign an Acquisition

Culture in M&A: What Everyone Knows… and What Is Voluntarily Kept Outside the Deal

If you are reading this, you may be about to make — or approve — an acquisition.
You have numbers, synergies, scenarios, legal risks, a tight timeline, and solid advisors. Everything appears “under control.”

And yet, there is a recurring paradox in M&A transactions:
culture is not a misunderstood topic. It is a consciously sidelined one.

Not because it is secondary, but because it does not fit the dominant logic of the deal.

On the transaction side, the same sentences come up again and again, almost word for word:

• “We are asked for numbers.”
• “It’s not part of the process.”
• “It doesn’t fit into the models.”
• “We don’t have time.”
• “There is no standard framework for cultural due diligence.”

It is pragmatic.
It is coherent…
and it is revealing.

The Real Blind Spot: A Question Rarely Asked Before Signing

At the negotiation table, one essential question is often left implicit — or postponed to “integration”:

Will these organisations (and above all, the people who lead them) actually be able to work together?

Not “in theory.”
Not “on paper.”

In day-to-day reality: decisions, conflicts, power, priorities, behaviours.

Answering this question requires examining dimensions that are rarely explored before signing, such as:

• how leadership exercises authority — and reacts when it is challenged,
• how decisions are truly made (or avoided, or imposed),
• what teams say when official communication stops,
• what your customers already perceive: internal coherence, responsiveness, reliability, trust.

These dimensions are not set aside because they are “fuzzy.”

They are set aside because they are uncomfortable: they challenge certainties, complicate the narrative of control, disrupt the timeline, and introduce variables that cannot easily be forced into a model.

So they are postponed.

A Rational Displacement of Responsibility

What is at play here is not merely a methodological issue.
It is a governance mechanism.

In M&A, responsibilities are often implicitly distributed as follows:

• Before signing: banks, advisors, deal teams, committees.
• After signing: executives, HR, managers, integration teams.

As a result, culture is structurally displaced:

• outside the deal calendar,
• outside immediate accountability,
• outside the performance criteria of transaction decision-makers.

This is not an oversight.

It is a rational transfer of burden:

What will produce effects later — and for which I will not be directly accountable — can be minimised today.

And that is precisely what makes the issue so costly.

Speed, Control… and the Illusion of Certainty

M&A mechanics favour what is measurable, comparable, and standardisable.

Legal and financial aspects — these are mastered, and mastered well.

Culture — trust, relationships, informal dynamics, power, unspoken rules — is harder to quantify. So it is pushed “downstream.”

Except that what is postponed does not disappear.

It comes back later in the form of passive resistance, disengagement, latent conflict, talent departures, customer loss, execution breakdowns, and synergies that never materialise.

In other words: what was deferred to gain speed and certainty upstream reappears downstream — with a much higher bill.

I hear this even from clear-eyed deal advisors:

“When we come back to culture, it’s already too late. Teams are exhausted, tensions are embedded, and trust has already taken hits.”

The Key Point: This Is Not an HR Topic. It Is a Governance Issue.

As long as culture remains filed under “post-deal / integration / soft issues,” the system will continue to produce the same outcome:

decide fast — then pay later.

The real leadership question is therefore no longer:
“Does culture matter?”

You already know the answer.

The question is:

When, where, and by whom is culture taken into account — at the moment decisions are made?

And above all:
what human and organisational impacts are you knowingly accepting by signing?

Three Questions to Bring Up Before Signing

Before signing — not after — force these questions up to the level where the decision is made:

1. Which human and cultural impacts are we consciously accepting?
   And which are incompatible with our responsibilities as executives and board members?
2. Which “fast decisions” are creating a deferred human cost that others will have to absorb later — managers, HR, integration teams, and above all, employees?
3. What qualitative information, if we had it today, could change the decision?
   Not to “tick a box,” but to avoid perfectly predictable value destruction.

Call to Action: What You Can Decide Right Now

If you are the deal sponsor — or if you have the power to say yes or no — here is the simplest (and most strategic) action you can take:

bring culture back into the decision perimeter, before signing.

Concretely, require these five elements immediately:

1. A cultural risk brief at the same level as legal and financial risk
   One page. Five to seven major human/cultural risks, their likely impacts, early warning signals, and non-negotiables.
2. A focused cultural due diligence (fast, but real)
   Not a slogan workshop. A field inquiry: leadership interviews, manager listening, key irritants, implicit norms, power dynamics, customer perception.
3. A top-management alignment test before signing
   Decision-making, conflict, autonomy, control, governance. If leadership styles are incompatible, this is not a detail — it is a strategic risk.
4. An integration governance clause
   Who decides what, how, at what pace — and how deadlocks are resolved. Culture shows up in decisions and conflict, not in slides.
5. An explicit no-go
   Define, before signing, the human and cultural incompatibilities that must stop, renegotiate, or reconfigure the deal. Without this, you do not have a safeguard — you have a belief.

Closing Words

Culture does not appear directly in financial models.

But it shapes the real trajectory of an acquisition: speed of execution, trust, retention, decision quality, and the ability to deliver on promises made to the market.

In many deals, cultural failure is neither a mystery nor a surprise.

It is often anticipated… and left outside the perimeter.

Reintegrating these dimensions earlier is not a moral stance.

It is a responsible governance decision.

So if you are about to sign, I will leave you with this simple sentence:

If you do not decide on culture before signing, you will still decide — later, painfully, and at a much higher cost.