Before Iceland became the large-scale reference point, a New Zealand firm gave the four-day week its first widely reported business case.
Perpetual Guardian, a trusts and estates company with about 240 staff, ran an eight-week trial in 2018. Staff were paid for five days, worked four, and were asked to maintain their output. The trial was monitored by academics from Auckland universities, which is one reason it still carries weight: the company did not grade its own homework.
At Day5Group, we help organisations transition to a four-day week. Perpetual Guardian is useful to our clients not because it was perfect, but because it shows what a well-run, bounded trial looks like in a regulated, client-facing business.
How the trial was set up
Founder Andrew Barnes framed the offer as a bargain, not a perk. Staff received a day away from work; in return, teams were expected to think hard about how they used the remaining four. Meetings, interruptions and low-value routines were all open to challenge.
That framing matters. A day given with no expectation invites the fifth day’s work to pile into the other four. A day exchanged for better working methods gives teams permission to stop, shorten and automate.
The academic monitoring measured staff experience before and after, alongside the company’s view of performance. That combination — output and lived experience — is the minimum any serious pilot should copy.
What changed
The reported results were striking for the wellbeing measures. The share of staff reporting stress fell from 45% to 38%. Scores for work-life balance rose from 54% to 78%. Researchers also reported sharp improvements in areas such as leadership, commitment and empowerment, suggesting staff did not just feel less tired; they felt more trusted to organise their work.
The company reported that output was maintained during the trial, and Barnes spoke publicly of a productivity improvement of around 20%. Read that last figure with care. It is a founder’s reported assessment from a single firm over eight weeks, not a universal rate you can budget for. The defensible claim from Perpetual Guardian is steadier and, for most boards, sufficient: the work still got done, clients were still served, and staff were measurably better for the change.
After the trial, the company made the four-day week permanent, with staff able to opt into the arrangement under agreed conditions.
Why it worked there
Three features stand out.
First, leadership gave time and asked for redesign in return. Staff were not told to absorb five days of unchanged work into four.
Second, the trial was short enough to focus effort, but measured properly. A before-and-after view of stress and balance, taken by independent academics, made the end-of-trial conversation concrete.
Third, the firm was honest that permanence needed rules. Opt-in arrangements, output expectations and client coverage were written down, rather than left to goodwill.
The limits you should keep in mind
Perpetual Guardian is one firm, in one country, with a motivated founder and a workforce that knew it was part of something watched. Eight weeks can capture novelty as well as lasting change. Knowledge and client work of this kind is also easier to reorganise than a 24-hour roster.
None of that invalidates the case. It defines how to use it: as proof that a monitored trial can maintain output, and as a template for running your own, not as a promise of identical percentages.
What to copy in your own trial
Borrow the structure, not just the headline.
- Announce a genuine trial, with a start, an end and a decision date.
- Ask each team to name the outputs that must not fall.
- Invite staff to propose meetings and processes to stop or shrink — then act on the list visibly.
- Measure stress, balance and workload before you start, not from memory afterwards.
- Use an outside eye where you can, even if it is only a peer manager from another function scoring the results.
Perpetual Guardian’s lasting contribution is not a single percentage. It is the demonstration that a firm can treat time as a design variable, test it in the open, and keep the change because the evidence supports it.
Sources
- Perpetual Guardian trial, New Zealand (2018), academic monitoring by Auckland universities — reported in ScienceAlert, 2018: https://www.sciencealert.com/this-4-day-work-week-experiment-went-so-well-company-keeping-it-perpetual-guardian-engagement-balance
Day5Group is a consultancy that assists in the transition to a 4 day work week. More about Day5Group · All blog articles