While it's "hard to know" when a four-day workweek will arrive for the majority of the working population, Cohen said investing in experiences would likely be the best way to benefit from the major theme of Americans working fewer hours.

"Anything around, you know, I would say leisure, travel, experiences, all that type of that stuff, if people have more time," Cohen said of the investment implications from a four-day workweek. 

Cohen himself has made major investments in the sports world. Aside from his 95% ownership stake in the New York Mets, Cohen recently joined a group of investors committed to putting about $3 billion into the PGA Tour.

"That should fit into a theme of more leisure for people, which means golf rounds will go up, and you know, interest," Cohen said. "I guess courses will be crowded on Fridays."

While Cohen expects a four-day workweek to eventually become reality, it probably won't for his employees or anyone else employed by investment firms. That is, unless the stock market also decides to adopt a four-day workweek.

"If they're taking off Friday and they have a portfolio, that's a problem, OK, if the markets are open," Cohen said of investment managers. "So forget, forgetting us, OK. I mean, the vast majority of people will get an opportunity, I think at some point, to have a three-day weekend."