In the UK, where more than 70 organisations signed up for the trial, 88 per cent of respondents reported that the four-day week was working "well" for their business at this stage in the trial.
Forty-six per cent of respondents said productivity has "maintained around the same level", while 34 per cent reported it has "improved slightly", and 15 per cent noted productivity had "improved significantly".
So could the four-day work week be here to stay?
Well, 86 per cent of respondents think so, saying that they would be "extremely likely" and/or "likely" to consider retaining the four-day week policy after the trial period.
Joe O'Connor, 4 Day Week Global chief executive, said the real-time data and knowledge being contributed was worth its weight in gold.
"They [the organisations] are laying the foundation for the future of work by putting a four-day week into practice, across every size of business and nearly every sector, and telling us exactly what they are finding as they go.
"We are learning that for many it is a fairly smooth transition and for some there are some understandable hurdles – especially among those which have comparatively fixed or inflexible practices, systems, or cultures which date back well into the last century.
"While for most organisations the pilot prompts many pleasing discoveries and outcomes – a lot of businesses have more flexibility and nimbleness among their people and teams that leaders often know at the outset – there is friction for others, and this can be based on a variety of factors, many of which can be addressed or substantially improved in the pilot itself."
On this side of the world, more than 20 companies from Australia and New Zealand are taking part in the four-day work week trial which began last month and is due to end in January 2023.
Perpetual Guardian's Barnes made headlines in 2018 when he introduced a four-day work week at the financial trust, turning an experiment from earlier that year into company policy.
Barnes had previously told the AM show that "productivity has gone up, our profits have gone up, our staff retention has improved, our stress levels have dropped."
And some of these benefits have been realised from those organisations participating in the UK trial.
Claire Daniels, chief executive of Leeds-based marketing agency Trio Media, said: "The four-day week trial so far has been extremely successful for us. Productivity has remained high, with an increase in wellness for the team, along with our business performing 44 per cent better financially."
Nicci Russell, managing director of Waterwise - an independent, not-for-profit focused on reducing water consumption in the UK, said while initially a learning curve, the trial was now going well.
"It wasn't a walk in the park at the start, but no major change ever is, and we were well briefed and prepared by the 4 Day Week Global team," she said.
"We certainly all love the extra day out of the office and do come back refreshed. It's been great for our wellbeing and we're definitely more productive already."