Jan Kleijn leaves Mammoet: a blessing or a warning?

On 1 February 2027, Jan Kleijn is due to leave Mammoet after 30 years. Starting in operations and logistics, he rose to CEO and has been COO since 2017. For fifteen years he has held top leadership roles. Mammoet highlights his commitment to talent, culture and opportunities for others.¹

He knows what worked, what failed and what it took to move forward. His departure poses a question larger than appointing a replacement: what else walks out when an experienced leader leaves?

A new chapter. What should remain?

Kleijn's departure was announced after another attempt by SHV to sell Mammoet reportedly fell through.² Mammoet described his move as a decision to pass the baton to a new generation, with a carefully managed transition. Its statement did not establish a connection with the sale process.

What matters is how the transition makes room for fresh leadership while preserving what made the company strong.

What spreadsheets cannot measure

Revenue, margin, productivity, utilisation and return are necessary management indicators. But a dashboard rarely shows who retained a customer's trust during a crisis, prevented a problem before it arose or took responsibility when the solution was unclear.

Dedication has no standard column in a management report.

Loyalty, hands-on judgment, entrepreneurship and mutual trust can determine how well a company performs under pressure. That does not make endless overtime a sustainable model. Good leaders recognise exceptional commitment while preventing dependence on the sacrifice of a few people.

You can fill a position. You must transfer experience.

Succession plans list responsibilities, authority and targets. But the unwritten knowledge is often more fragile: why certain agreements exist, which customers require particular attention and when an established procedure needs practical judgment.

Start the handover well before the final working day. Involve successors in difficult conversations. Review decisions that failed. Transfer relationships together. Ask experienced colleagues what they notice when the numbers look right but the situation does not feel right.

Understand what made the organisation successful

Change is sometimes necessary. “We have always done it this way” is not enough of an argument. Neither is “we must become more professional.” What exactly will improve?

Clearer information and less dependence on individuals may help. Extra approval layers that stop an employee solving a customer's problem may not. Visit the workplace and learn which habits support success and which merely survived.

Entrepreneurship needs room and boundaries

Executives and shareholders shape the room people have to act. Clear standards for safety, quality and financial discipline are vital. Inside those standards, people need the authority to make decisions and a leader they can turn to when the judgment is difficult.

Blessing or warning?

An experienced leader's departure can create opportunities for the next generation. It is a blessing when knowledge and culture are handed on. It is a warning when experience vanishes and people lose the freedom to make decisions.

Which way Mammoet will go remains to be seen. Its announced focus on continuity provides a starting point.

What should still define your company's strength in five years?

KPIs show what was achieved. They do not reveal everything people gave to get there.

Ei Openers helps leaders with succession, entrepreneurship and organisational development. Start a conversation.

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