By Dean, Founder of Hunter Adams
When businesses talk about mergers and acquisitions (M&A), they often focus on strategy, valuation, and commercial synergy. But behind every deal are people. And without aligning the people and culture on both sides of the table, even the most financially sound M&A deals can fall short.
So, what is a merger or acquisition?
A merger is when two businesses combine to become one, while an acquisition is when one company buys another. The process is complex, involving finance, legal, and operational integration. But amid all that complexity, cultural due diligence is often overlooked.
What is company culture?
When we talk about “culture” in M&A, we’re not referring to national customs or broad societal behaviours. We mean company culture, the shared values, behaviours, leadership styles, and working norms that shape how things get done in an organisation.
It’s how decisions are made, how people communicate, what’s rewarded (or tolerated), and what it feels like to be part of the business. When two companies merge, you’re bringing together two sets of cultural DNA. And without understanding those differences, friction is inevitable.
The hidden dealbreaker: cultural misalignment
Studies show that between 70% and 90% of M&A deals fail to deliver expected value, and culture is a significant reason why. A 2009 Deloitte report on cultural issues in business mergers and acquisitions warned that culture clashes and misalignment can derail integration and damage employee engagement. Yet, 17 years later, it’s still being overlooked.
A recent EY UK and Oxford Saïd Business School study found that organisations taking a human-centred approach to integration are nearly three times more likely to succeed. Quite staggering stats, I thought. Culture in mergers and acquisitions isn’t ‘soft stuff’. It’s a commercial lever.
Culture clash: the cost of overlooking people
When two businesses come together, it’s not just processes that merge, it’s people, behaviours, values and expectations. Without proper planning, this creates confusion, resistance, and poor retention. Suddenly, your high-potential acquisition becomes a talent risk.
I’ve seen company culture derail deals that looked perfect on paper. The financials stacked up. The legal boxes were ticked. But without shared values and clear communication, the cracks appeared fast. Inconsistent leadership messages. Resistance to new processes. Key people walk out.
And the impact isn’t short-term. Cultural misalignment can affect employee engagement, performance and long-term business growth. That’s why cultural integration in mergers and acquisitions needs the same rigour as financial planning.
HR’s role in mitigating post-deal risk
At Hunter Adams, we believe HR should be embedded in the M&A process from day one and not brought in after the ink is dry. From HR due diligence to people integration planning, Human Resources can de-risk the entire journey.
Before the deal, we support:
- Cultural assessments
- Leadership alignment
- Organisational culture audits
- Employee experience mapping
Then during integration, we focus on:
- Workplace culture alignment
- Change communication
- Retention planning
- Executive coaching and leadership development
And we stay involved post-deal to support culture transformation and keep people engaged.
Explore our M&A HR Support Services
Leadership alignment: the glue that holds it together
One of the most powerful ways to avoid a culture clash is to align leadership early. That means shared language, clear goals, and consistent behaviours. When leaders send mixed signals, the rest of the business feels the gap.
Our leadership development programmes are designed to bring leadership teams together, building capability and cohesion across merged organisations.
In one recent integration project, we supported two exec teams through facilitated sessions that identified friction points, clarified decision-making authority, and mapped cultural differences. This built trust and avoided post-deal conflict.
Employee engagement: your early warning system
Employee engagement is more than a pulse survey. It’s a barometer of cultural health. During M&A, it can be your early warning system for cultural issues and a powerful tool to monitor how people are adapting.
We recommend measuring engagement before, during and after integration. This gives leadership teams insight into where support is needed, where messaging isn’t landing, or where change fatigue is setting in.
Our employee engagement services provide that support, helping businesses keep their best people and avoid post-deal attrition.
Building trust and understanding during integration
A common reason cultural challenges emerge is a lack of effective communication. Employees don’t know what’s changing, why it’s happening, or how it will affect them. This uncertainty breeds fear, disengagement, and resistance.
That’s why integration strategies must prioritise employee understanding. Clear, consistent communication builds trust, helps teams navigate change, and fosters cultural fit. Without it, you risk losing human capital and derailing your strategic goals.
We work closely with management teams to develop communication plans that align with company values, address employee concerns, and reinforce the acquiring company’s long-term vision. It’s about creating a narrative that people can connect to, one that leads to a successfully integrated workforce.
Mental health and human capital: the often-ignored impact
M&A activities put real pressure on people. Job insecurity, shifting team dynamics, and cultural uncertainty can affect mental health, especially when there’s poor communication or a lack of clarity around roles.
But there’s another layer we see often during integrations, one that’s rarely spoken about. The internal politics and positioning that play out can be intense. When individuals feel they’re at risk of being replaced or overshadowed by their counterparts from the other organisation, tensions rise. In extreme cases, it can border on sabotage. It’s like watching the House of Commons; performance, power plays, and pressure. And when fear takes over, people can lose sight of values.
That’s why values need to be visible and upheld throughout. Leaders must create an environment where behaviour is addressed, people are supported, and accountability is clear. Cultural alignment isn’t just about workshops and surveys, it’s about how people actually show up and treat one another during times of change.
As part of our integration support, we always consider the impact on mental health and well-being. This isn’t just ‘the right thing to do’, as it really supports long-term success. When employees feel safe and supported, they’re more likely to stay, engage, and contribute to a positive culture.
Human capital is one of the most valuable assets in any M&A transaction. Yet it’s often the most neglected. By integrating well-being into your M&A process, you create conditions for resilience and retention, not burnout and attrition.
How to approach cultural due diligence
Cultural due diligence should be a core part of your M&A checklist. This means:
- Assessing corporate culture and values on both sides
- Identifying cultural risks and mismatches
- Involving employees early in the process
- Planning for cross-cultural integration challenges
The earlier the culture surfaces, the more effectively it can be managed.
As found in a recent study by EY and Oxford Saïd (2025), assuming cultural similarity is one of the biggest blind spots in M&A. Similarity often creates complacency, hiding critical differences until it’s too late.
Culture isn’t fluff. It’s foundational.
If you’re leading or advising on M&A deals, don’t let culture be an afterthought. It’s not just about making people feel good, although this is important. It’s also about protecting the value of your deal.
As Harvard Business Review noted in 2025, many deals fail not because of the commercial strategy, but because integration lacked cultural alignment and structured planning. HBR also found that mapping employee experience journeys post-deal is one of the most effective ways to keep culture on track.
M&A success depends on much more than spreadsheets and signatures. It’s about humans, values, and behaviours. And getting that right takes intention, insight, and the right partner.
If you’re planning a deal, or struggling post-acquisition, let’s have a chat about how we can help.
Talk to our team or learn more about M&A HR support.
