The Telmex and America Movil mogul says 40% of staff offered the deal have adopted the three-day week.
Carlos Slim, the richest man in Mexico, has said he wants to introduce a three-day work week and a later retirement age to counterbalance changes in the way that civilisation is living and working.
Mr Slim said any sector where productivity demands have led to excess personnel would be suitable for these changes, such as government agencies.
"It’s a great change to exchange fewer days of work for more years until retirement. In fact, we started this in Telmex [América Móvil’s fixed-line unit] a couple of years ago. We’re offering people that have a lot of knowledge to stay longer and work fewer days," he told Bloomberg Businessweek.
Mr Slim made his billions in the telecommunications industry as the chairman and chief executive of Telmex and America Movil, the biggest mobile-phone carrier in Latin America.
He first started talking about a three-day week in 2014, as technological improvements mean machines can run 24-hours a day while people work shorter weeks, for longer in life. The plan would allow more jobs for younger people and better expertise from older workers staying on longer.
Mr Slim said he has since offered the three-day week idea to staff and that around 40 per cent of staff offered the deal have taken him up on it.
The scheme could work for bloated teams that need to make cuts by allowing them to have more workers, pay more salaries, but avoid having to pay when workers retire early.
Changes to the work week are nothing new in civilisation, Mr Slim said.
"Before they worked 72 hours, six days a week. Then 60 hours. The big success was the 48-hour workweek. Then the English week, where you worked Saturday and only rested on Sundays. Then 40 hours. Instead of working five days, for 35 hours, let’s just work three days to make room for others to work," he said.