Pioneers in Sustainable HRM Policy: Marieke Pepers, CHRO of Nmbrs

The sustainable HRM policy of Nmbrs, a developer of HR and payroll software with offices in Amsterdam, Lisbon, and Stockholm and 150 employees, is so successful it almost sounds too good to be true. But their results prove otherwise: an eNPS of 87, just one resignation every six months, and productivity that increased even after switching to a four-day workweek.

At ImpactWork, we are constantly looking for organizations that show sustainable HR transformation is more than just words on paper. That’s why, in this interview series, we speak with trailblazers who have proven that a radically different approach can work. 

CHRO Marieke Pepers of Nmbrs kicks off the series and shares how she led this transformation — and what other organizations can learn from it.

The Power of a Four-Day Workweek

How do you achieve such results? For Nmbrs it started in 2022 with a bold step: as one of the first organizations in the Netherlands, the company introduced the four-day workweek, with Fridays off for everyone. What was then still seen in the market as a rigid approach has exceeded all expectations.

"The four-day workweek has created a clear distinction between work and private life, without the constant pressure of late-night messages or emails over the weekend," Marieke explains. Productivity increased significantly, and the eNPS climbed spectacularly from 50 to 70, and recently even to 87.

The week follows a fixed rhythm:

Monday through Wednesday: Teams work for three days on their ‘sprint’ to achieve pre-set goals.

Wednesday evening: Tech update of the software, which was prepared during the sprints.

Thursday morning: ‘Follow-up’ and planning for the next week.

Thursday afternoon: Team members come together in ‘discipline groups’ to improve working methods.

Trust over control: working without managers

Today, a four-day workweek is no longer unique, but Nmbrs’ team structure certainly is. Despite 150 employees spread over three countries, there are no managers or team leaders. The management team focuses solely on direction and vision – the daily work is done by self-managing teams.

According to Marieke, her colleagues receive a great deal of trust and space to make the right decisions through this sustainable business model. "We don’t have a process for everything." We have a few basic principles, and the rest is up to the team. “And that team also sets the bar very high," Marieke summarizes the philosophy. This approach is supported by built-in reflection moments. The social control within teams and open communication ensure that the output remains at a high level and that everyone knows what is expected of them.

Extremely low employee turnover

Nmbrs’ approach clearly pays off. In addition to the remarkable rise in eNPS, the company has a very low employee turnover. The organization also has a notably high number of ‘boomerangers’, or employees who return after leaving. Marieke sees this as proof of a serious, sustainable working environment: "Right now, we’re seeing that we have one resignation every six months. For us, these are the numbers that matter." To continue monitoring employee well-being, an engagement survey is conducted every month. To continue monitoring employee well-being, a monthly engagement survey is conducted.

360-Degree Transparency: When Colleagues Determine Your Salary

According to Marieke, a crucial factor in their low turnover is the way performance is assessed. Twice a year, teammates evaluate each other’s performance through a 360-degree review. The feedback, including a numerical score, takes place entirely without managers and directly determines the salary increase.
"This transparent and fair approach strengthens collaboration and the sense of ownership within the teams," she explains. The compensation policy is linked to the market (50th–70th percentile). In the case of overtime, employees receive compensation in the form of time off, which they can take during quieter periods.

HR Challenges of a Front-Runner

Such a radical approach naturally also brings challenges, especially now that Nmbrs is in a growth phase. "We’re growing from 154 to 180 employees," Marieke explains. "Onboarding new people into this unique way of working and maintaining short lines of communication without managers remains an important point of attention."

That’s why the recruitment process is crucial and entirely focused on cultural fit. The process includes four clear steps: a cultural interview, a conversation with the recruiter, a technical interview, and a final interview with a Chapter Lead.

Lessons for Other Organizations

Nmbrs' approach shows that traditional management structures are not a requirement for success. Their sustainable HRM policy is built on five pillars:

1. Autonomous teams without managers: Trust in self-managing teams that take ownership.
2. Four-day workweek: Compressed workweek for higher productivity and better balance.
3. Strict work-life separation: A clear culture where both domains remain distinct.
4. 360-degree performance reviews: Democratic, transparent evaluation by colleagues.
5. Cultural recruitment: Hiring focused on fit, not just skills.

"What can other organizations learn from this?" Marieke pauses for a moment. "Start small, but be consistent. Giving trust also means letting go. And more importantly: make sure you truly put people at the center — not just in your mission, but in every decision you make."